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71bfa161 JA |
1 | Table of contents |
2 | ----------------- | |
3 | ||
4 | 1. Overview | |
5 | 2. How fio works | |
6 | 3. Running fio | |
7 | 4. Job file format | |
8 | 5. Detailed list of parameters | |
9 | 6. Normal output | |
10 | 7. Terse output | |
25c8b9d7 | 11 | 8. Trace file format |
43f09da1 | 12 | 9. CPU idleness profiling |
71bfa161 JA |
13 | |
14 | 1.0 Overview and history | |
15 | ------------------------ | |
16 | fio was originally written to save me the hassle of writing special test | |
17 | case programs when I wanted to test a specific workload, either for | |
18 | performance reasons or to find/reproduce a bug. The process of writing | |
19 | such a test app can be tiresome, especially if you have to do it often. | |
20 | Hence I needed a tool that would be able to simulate a given io workload | |
21 | without resorting to writing a tailored test case again and again. | |
22 | ||
23 | A test work load is difficult to define, though. There can be any number | |
24 | of processes or threads involved, and they can each be using their own | |
25 | way of generating io. You could have someone dirtying large amounts of | |
26 | memory in an memory mapped file, or maybe several threads issuing | |
27 | reads using asynchronous io. fio needed to be flexible enough to | |
28 | simulate both of these cases, and many more. | |
29 | ||
30 | 2.0 How fio works | |
31 | ----------------- | |
32 | The first step in getting fio to simulate a desired io workload, is | |
33 | writing a job file describing that specific setup. A job file may contain | |
34 | any number of threads and/or files - the typical contents of the job file | |
35 | is a global section defining shared parameters, and one or more job | |
36 | sections describing the jobs involved. When run, fio parses this file | |
37 | and sets everything up as described. If we break down a job from top to | |
38 | bottom, it contains the following basic parameters: | |
39 | ||
40 | IO type Defines the io pattern issued to the file(s). | |
41 | We may only be reading sequentially from this | |
42 | file(s), or we may be writing randomly. Or even | |
43 | mixing reads and writes, sequentially or randomly. | |
44 | ||
45 | Block size In how large chunks are we issuing io? This may be | |
46 | a single value, or it may describe a range of | |
47 | block sizes. | |
48 | ||
49 | IO size How much data are we going to be reading/writing. | |
50 | ||
51 | IO engine How do we issue io? We could be memory mapping the | |
52 | file, we could be using regular read/write, we | |
d0ff85df | 53 | could be using splice, async io, syslet, or even |
71bfa161 JA |
54 | SG (SCSI generic sg). |
55 | ||
6c219763 | 56 | IO depth If the io engine is async, how large a queuing |
71bfa161 JA |
57 | depth do we want to maintain? |
58 | ||
59 | IO type Should we be doing buffered io, or direct/raw io? | |
60 | ||
61 | Num files How many files are we spreading the workload over. | |
62 | ||
63 | Num threads How many threads or processes should we spread | |
64 | this workload over. | |
66c098b8 | 65 | |
71bfa161 JA |
66 | The above are the basic parameters defined for a workload, in addition |
67 | there's a multitude of parameters that modify other aspects of how this | |
68 | job behaves. | |
69 | ||
70 | ||
71 | 3.0 Running fio | |
72 | --------------- | |
73 | See the README file for command line parameters, there are only a few | |
74 | of them. | |
75 | ||
76 | Running fio is normally the easiest part - you just give it the job file | |
77 | (or job files) as parameters: | |
78 | ||
79 | $ fio job_file | |
80 | ||
81 | and it will start doing what the job_file tells it to do. You can give | |
82 | more than one job file on the command line, fio will serialize the running | |
83 | of those files. Internally that is the same as using the 'stonewall' | |
550b1db6 | 84 | parameter described in the parameter section. |
71bfa161 | 85 | |
b4692828 JA |
86 | If the job file contains only one job, you may as well just give the |
87 | parameters on the command line. The command line parameters are identical | |
88 | to the job parameters, with a few extra that control global parameters | |
89 | (see README). For example, for the job file parameter iodepth=2, the | |
c2b1e753 JA |
90 | mirror command line option would be --iodepth 2 or --iodepth=2. You can |
91 | also use the command line for giving more than one job entry. For each | |
92 | --name option that fio sees, it will start a new job with that name. | |
93 | Command line entries following a --name entry will apply to that job, | |
94 | until there are no more entries or a new --name entry is seen. This is | |
95 | similar to the job file options, where each option applies to the current | |
96 | job until a new [] job entry is seen. | |
b4692828 | 97 | |
71bfa161 JA |
98 | fio does not need to run as root, except if the files or devices specified |
99 | in the job section requires that. Some other options may also be restricted, | |
6c219763 | 100 | such as memory locking, io scheduler switching, and decreasing the nice value. |
71bfa161 JA |
101 | |
102 | ||
103 | 4.0 Job file format | |
104 | ------------------- | |
105 | As previously described, fio accepts one or more job files describing | |
106 | what it is supposed to do. The job file format is the classic ini file, | |
107 | where the names enclosed in [] brackets define the job name. You are free | |
108 | to use any ascii name you want, except 'global' which has special meaning. | |
109 | A global section sets defaults for the jobs described in that file. A job | |
110 | may override a global section parameter, and a job file may even have | |
111 | several global sections if so desired. A job is only affected by a global | |
65db0851 JA |
112 | section residing above it. If the first character in a line is a ';' or a |
113 | '#', the entire line is discarded as a comment. | |
71bfa161 | 114 | |
3c54bc46 | 115 | So let's look at a really simple job file that defines two processes, each |
b22989b9 | 116 | randomly reading from a 128MB file. |
71bfa161 JA |
117 | |
118 | ; -- start job file -- | |
119 | [global] | |
120 | rw=randread | |
121 | size=128m | |
122 | ||
123 | [job1] | |
124 | ||
125 | [job2] | |
126 | ||
127 | ; -- end job file -- | |
128 | ||
129 | As you can see, the job file sections themselves are empty as all the | |
130 | described parameters are shared. As no filename= option is given, fio | |
c2b1e753 JA |
131 | makes up a filename for each of the jobs as it sees fit. On the command |
132 | line, this job would look as follows: | |
133 | ||
134 | $ fio --name=global --rw=randread --size=128m --name=job1 --name=job2 | |
135 | ||
71bfa161 | 136 | |
3c54bc46 | 137 | Let's look at an example that has a number of processes writing randomly |
71bfa161 JA |
138 | to files. |
139 | ||
140 | ; -- start job file -- | |
141 | [random-writers] | |
142 | ioengine=libaio | |
143 | iodepth=4 | |
144 | rw=randwrite | |
145 | bs=32k | |
146 | direct=0 | |
147 | size=64m | |
148 | numjobs=4 | |
149 | ||
150 | ; -- end job file -- | |
151 | ||
152 | Here we have no global section, as we only have one job defined anyway. | |
153 | We want to use async io here, with a depth of 4 for each file. We also | |
b22989b9 | 154 | increased the buffer size used to 32KB and define numjobs to 4 to |
71bfa161 | 155 | fork 4 identical jobs. The result is 4 processes each randomly writing |
b22989b9 | 156 | to their own 64MB file. Instead of using the above job file, you could |
b4692828 JA |
157 | have given the parameters on the command line. For this case, you would |
158 | specify: | |
159 | ||
160 | $ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4 | |
71bfa161 | 161 | |
74929ac2 JA |
162 | 4.1 Environment variables |
163 | ------------------------- | |
164 | ||
3c54bc46 AC |
165 | fio also supports environment variable expansion in job files. Any |
166 | substring of the form "${VARNAME}" as part of an option value (in other | |
167 | words, on the right of the `='), will be expanded to the value of the | |
168 | environment variable called VARNAME. If no such environment variable | |
169 | is defined, or VARNAME is the empty string, the empty string will be | |
170 | substituted. | |
171 | ||
172 | As an example, let's look at a sample fio invocation and job file: | |
173 | ||
174 | $ SIZE=64m NUMJOBS=4 fio jobfile.fio | |
175 | ||
176 | ; -- start job file -- | |
177 | [random-writers] | |
178 | rw=randwrite | |
179 | size=${SIZE} | |
180 | numjobs=${NUMJOBS} | |
181 | ; -- end job file -- | |
182 | ||
183 | This will expand to the following equivalent job file at runtime: | |
184 | ||
185 | ; -- start job file -- | |
186 | [random-writers] | |
187 | rw=randwrite | |
188 | size=64m | |
189 | numjobs=4 | |
190 | ; -- end job file -- | |
191 | ||
71bfa161 JA |
192 | fio ships with a few example job files, you can also look there for |
193 | inspiration. | |
194 | ||
74929ac2 JA |
195 | 4.2 Reserved keywords |
196 | --------------------- | |
197 | ||
198 | Additionally, fio has a set of reserved keywords that will be replaced | |
199 | internally with the appropriate value. Those keywords are: | |
200 | ||
201 | $pagesize The architecture page size of the running system | |
202 | $mb_memory Megabytes of total memory in the system | |
203 | $ncpus Number of online available CPUs | |
204 | ||
205 | These can be used on the command line or in the job file, and will be | |
206 | automatically substituted with the current system values when the job | |
892a6ffc JA |
207 | is run. Simple math is also supported on these keywords, so you can |
208 | perform actions like: | |
209 | ||
210 | size=8*$mb_memory | |
211 | ||
212 | and get that properly expanded to 8 times the size of memory in the | |
213 | machine. | |
74929ac2 | 214 | |
71bfa161 JA |
215 | |
216 | 5.0 Detailed list of parameters | |
217 | ------------------------------- | |
218 | ||
219 | This section describes in details each parameter associated with a job. | |
220 | Some parameters take an option of a given type, such as an integer or | |
221 | a string. The following types are used: | |
222 | ||
223 | str String. This is a sequence of alpha characters. | |
b09da8fa | 224 | time Integer with possible time suffix. In seconds unless otherwise |
e417fd66 | 225 | specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds, |
0de5b26f JA |
226 | minutes, and hours, and accepts 'ms' (or 'msec') for milliseconds, |
227 | and 'us' (or 'usec') for microseconds. | |
b09da8fa JA |
228 | int SI integer. A whole number value, which may contain a suffix |
229 | describing the base of the number. Accepted suffixes are k/m/g/t/p, | |
230 | meaning kilo, mega, giga, tera, and peta. The suffix is not case | |
57fc29fa JA |
231 | sensitive, and you may also include trailing 'b' (eg 'kb' is the same |
232 | as 'k'). So if you want to specify 4096, you could either write | |
b09da8fa | 233 | out '4096' or just give 4k. The suffixes signify base 2 values, so |
57fc29fa JA |
234 | 1024 is 1k and 1024k is 1m and so on, unless the suffix is explicitly |
235 | set to a base 10 value using 'kib', 'mib', 'gib', etc. If that is the | |
236 | case, then 1000 is used as the multiplier. This can be handy for | |
237 | disks, since manufacturers generally use base 10 values when listing | |
238 | the capacity of a drive. If the option accepts an upper and lower | |
239 | range, use a colon ':' or minus '-' to separate such values. May also | |
240 | include a prefix to indicate numbers base. If 0x is used, the number | |
241 | is assumed to be hexadecimal. See irange. | |
71bfa161 JA |
242 | bool Boolean. Usually parsed as an integer, however only defined for |
243 | true and false (1 and 0). | |
b09da8fa | 244 | irange Integer range with suffix. Allows value range to be given, such |
bf9a3edb | 245 | as 1024-4096. A colon may also be used as the separator, eg |
0c9baf91 JA |
246 | 1k:4k. If the option allows two sets of ranges, they can be |
247 | specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see | |
f7fa2653 | 248 | int. |
83349190 | 249 | float_list A list of floating numbers, separated by a ':' character. |
71bfa161 JA |
250 | |
251 | With the above in mind, here follows the complete list of fio job | |
252 | parameters. | |
253 | ||
254 | name=str ASCII name of the job. This may be used to override the | |
255 | name printed by fio for this job. Otherwise the job | |
c2b1e753 | 256 | name is used. On the command line this parameter has the |
6c219763 | 257 | special purpose of also signaling the start of a new |
c2b1e753 | 258 | job. |
71bfa161 | 259 | |
61697c37 JA |
260 | description=str Text description of the job. Doesn't do anything except |
261 | dump this text description when this job is run. It's | |
262 | not parsed. | |
263 | ||
3776041e | 264 | directory=str Prefix filenames with this directory. Used to place files |
67445b63 JA |
265 | in a different location than "./". See the 'filename' option |
266 | for escaping certain characters. | |
71bfa161 JA |
267 | |
268 | filename=str Fio normally makes up a filename based on the job name, | |
269 | thread number, and file number. If you want to share | |
270 | files between threads in a job or several jobs, specify | |
ed92ac0c | 271 | a filename for each of them to override the default. If |
414c2a3e | 272 | the ioengine used is 'net', the filename is the host, port, |
0fd666bf | 273 | and protocol to use in the format of =host,port,protocol. |
414c2a3e JA |
274 | See ioengine=net for more. If the ioengine is file based, you |
275 | can specify a number of files by separating the names with a | |
276 | ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb | |
277 | as the two working files, you would use | |
30a4588a JA |
278 | filename=/dev/sda:/dev/sdb. On Windows, disk devices are |
279 | accessed as \\.\PhysicalDrive0 for the first device, | |
280 | \\.\PhysicalDrive1 for the second etc. Note: Windows and | |
281 | FreeBSD prevent write access to areas of the disk containing | |
282 | in-use data (e.g. filesystems). | |
283 | If the wanted filename does need to include a colon, then | |
284 | escape that with a '\' character. For instance, if the filename | |
285 | is "/dev/dsk/foo@3,0:c", then you would use | |
286 | filename="/dev/dsk/foo@3,0\:c". '-' is a reserved name, meaning | |
287 | stdin or stdout. Which of the two depends on the read/write | |
288 | direction set. | |
71bfa161 | 289 | |
de98bd30 JA |
290 | filename_format=str |
291 | If sharing multiple files between jobs, it is usually necessary | |
292 | to have fio generate the exact names that you want. By default, | |
293 | fio will name a file based on the default file format | |
294 | specification of jobname.jobnumber.filenumber. With this | |
295 | option, that can be customized. Fio will recognize and replace | |
296 | the following keywords in this string: | |
297 | ||
298 | $jobname | |
299 | The name of the worker thread or process. | |
300 | ||
301 | $jobnum | |
302 | The incremental number of the worker thread or | |
303 | process. | |
304 | ||
305 | $filenum | |
306 | The incremental number of the file for that worker | |
307 | thread or process. | |
308 | ||
309 | To have dependent jobs share a set of files, this option can | |
310 | be set to have fio generate filenames that are shared between | |
311 | the two. For instance, if testfiles.$filenum is specified, | |
312 | file number 4 for any job will be named testfiles.4. The | |
313 | default of $jobname.$jobnum.$filenum will be used if | |
314 | no other format specifier is given. | |
315 | ||
bbf6b540 JA |
316 | opendir=str Tell fio to recursively add any file it can find in this |
317 | directory and down the file system tree. | |
318 | ||
3776041e | 319 | lockfile=str Fio defaults to not locking any files before it does |
4d4e80f2 JA |
320 | IO to them. If a file or file descriptor is shared, fio |
321 | can serialize IO to that file to make the end result | |
322 | consistent. This is usual for emulating real workloads that | |
323 | share files. The lock modes are: | |
324 | ||
325 | none No locking. The default. | |
326 | exclusive Only one thread/process may do IO, | |
327 | excluding all others. | |
328 | readwrite Read-write locking on the file. Many | |
329 | readers may access the file at the | |
330 | same time, but writes get exclusive | |
331 | access. | |
332 | ||
d3aad8f2 | 333 | readwrite=str |
71bfa161 JA |
334 | rw=str Type of io pattern. Accepted values are: |
335 | ||
336 | read Sequential reads | |
337 | write Sequential writes | |
338 | randwrite Random writes | |
339 | randread Random reads | |
10b023db | 340 | rw,readwrite Sequential mixed reads and writes |
71bfa161 JA |
341 | randrw Random mixed reads and writes |
342 | ||
343 | For the mixed io types, the default is to split them 50/50. | |
344 | For certain types of io the result may still be skewed a bit, | |
211097b2 | 345 | since the speed may be different. It is possible to specify |
38dad62d JA |
346 | a number of IO's to do before getting a new offset, this is |
347 | one by appending a ':<nr>' to the end of the string given. | |
348 | For a random read, it would look like 'rw=randread:8' for | |
059b0802 | 349 | passing in an offset modifier with a value of 8. If the |
ddb754db | 350 | suffix is used with a sequential IO pattern, then the value |
059b0802 JA |
351 | specified will be added to the generated offset for each IO. |
352 | For instance, using rw=write:4k will skip 4k for every | |
353 | write. It turns sequential IO into sequential IO with holes. | |
354 | See the 'rw_sequencer' option. | |
38dad62d JA |
355 | |
356 | rw_sequencer=str If an offset modifier is given by appending a number to | |
357 | the rw=<str> line, then this option controls how that | |
358 | number modifies the IO offset being generated. Accepted | |
359 | values are: | |
360 | ||
361 | sequential Generate sequential offset | |
362 | identical Generate the same offset | |
363 | ||
364 | 'sequential' is only useful for random IO, where fio would | |
365 | normally generate a new random offset for every IO. If you | |
366 | append eg 8 to randread, you would get a new random offset for | |
211097b2 JA |
367 | every 8 IO's. The result would be a seek for only every 8 |
368 | IO's, instead of for every IO. Use rw=randread:8 to specify | |
38dad62d JA |
369 | that. As sequential IO is already sequential, setting |
370 | 'sequential' for that would not result in any differences. | |
371 | 'identical' behaves in a similar fashion, except it sends | |
372 | the same offset 8 number of times before generating a new | |
373 | offset. | |
71bfa161 | 374 | |
90fef2d1 JA |
375 | kb_base=int The base unit for a kilobyte. The defacto base is 2^10, 1024. |
376 | Storage manufacturers like to use 10^3 or 1000 as a base | |
377 | ten unit instead, for obvious reasons. Allow values are | |
378 | 1024 or 1000, with 1024 being the default. | |
379 | ||
771e58be JA |
380 | unified_rw_reporting=bool Fio normally reports statistics on a per |
381 | data direction basis, meaning that read, write, and trim are | |
382 | accounted and reported separately. If this option is set, | |
383 | the fio will sum the results and report them as "mixed" | |
384 | instead. | |
385 | ||
ee738499 JA |
386 | randrepeat=bool For random IO workloads, seed the generator in a predictable |
387 | way so that results are repeatable across repetitions. | |
388 | ||
04778baf JA |
389 | randseed=int Seed the random number generators based on this seed value, to |
390 | be able to control what sequence of output is being generated. | |
391 | If not set, the random sequence depends on the randrepeat | |
392 | setting. | |
393 | ||
2615cc4b JA |
394 | use_os_rand=bool Fio can either use the random generator supplied by the OS |
395 | to generator random offsets, or it can use it's own internal | |
396 | generator (based on Tausworthe). Default is to use the | |
397 | internal generator, which is often of better quality and | |
398 | faster. | |
399 | ||
a596f047 EG |
400 | fallocate=str Whether pre-allocation is performed when laying down files. |
401 | Accepted values are: | |
402 | ||
403 | none Do not pre-allocate space | |
404 | posix Pre-allocate via posix_fallocate() | |
405 | keep Pre-allocate via fallocate() with | |
406 | FALLOC_FL_KEEP_SIZE set | |
407 | 0 Backward-compatible alias for 'none' | |
408 | 1 Backward-compatible alias for 'posix' | |
409 | ||
410 | May not be available on all supported platforms. 'keep' is only | |
411 | available on Linux.If using ZFS on Solaris this must be set to | |
412 | 'none' because ZFS doesn't support it. Default: 'posix'. | |
7bc8c2cf | 413 | |
d2f3ac35 JA |
414 | fadvise_hint=bool By default, fio will use fadvise() to advise the kernel |
415 | on what IO patterns it is likely to issue. Sometimes you | |
416 | want to test specific IO patterns without telling the | |
417 | kernel about it, in which case you can disable this option. | |
418 | If set, fio will use POSIX_FADV_SEQUENTIAL for sequential | |
419 | IO and POSIX_FADV_RANDOM for random IO. | |
420 | ||
f7fa2653 | 421 | size=int The total size of file io for this job. Fio will run until |
7616cafe JA |
422 | this many bytes has been transferred, unless runtime is |
423 | limited by other options (such as 'runtime', for instance). | |
3776041e | 424 | Unless specific nrfiles and filesize options are given, |
7616cafe | 425 | fio will divide this size between the available files |
d6667268 | 426 | specified by the job. If not set, fio will use the full |
550b1db6 AG |
427 | size of the given files or devices. If the files do not |
428 | exist, size must be given. It is also possible to give | |
429 | size as a percentage between 1 and 100. If size=20% is | |
430 | given, fio will use 20% of the full size of the given | |
7bb59102 | 431 | files or devices. |
71bfa161 | 432 | |
77731b29 JA |
433 | io_limit=int Normally fio operates within the region set by 'size', which |
434 | means that the 'size' option sets both the region and size of | |
435 | IO to be performed. Sometimes that is not what you want. With | |
436 | this option, it is possible to define just the amount of IO | |
437 | that fio should do. For instance, if 'size' is set to 20G and | |
438 | 'io_limit' is set to 5G, fio will perform IO within the first | |
439 | 20G but exit when 5G have been done. | |
440 | ||
f7fa2653 | 441 | filesize=int Individual file sizes. May be a range, in which case fio |
9c60ce64 JA |
442 | will select sizes for files at random within the given range |
443 | and limited to 'size' in total (if that is given). If not | |
444 | given, each created file is the same size. | |
445 | ||
bedc9dc2 JA |
446 | file_append=bool Perform IO after the end of the file. Normally fio will |
447 | operate within the size of a file. If this option is set, then | |
448 | fio will append to the file instead. This has identical | |
0aae4ce7 JA |
449 | behavior to setting offset to the size of a file. This option |
450 | is ignored on non-regular files. | |
bedc9dc2 | 451 | |
74586c1e JA |
452 | fill_device=bool |
453 | fill_fs=bool Sets size to something really large and waits for ENOSPC (no | |
aa31f1f1 | 454 | space left on device) as the terminating condition. Only makes |
de98bd30 | 455 | sense with sequential write. For a read workload, the mount |
4f12432e JA |
456 | point will be filled first then IO started on the result. This |
457 | option doesn't make sense if operating on a raw device node, | |
458 | since the size of that is already known by the file system. | |
459 | Additionally, writing beyond end-of-device will not return | |
460 | ENOSPC there. | |
aa31f1f1 | 461 | |
f7fa2653 JA |
462 | blocksize=int |
463 | bs=int The block size used for the io units. Defaults to 4k. Values | |
464 | can be given for both read and writes. If a single int is | |
465 | given, it will apply to both. If a second int is specified | |
f90eff5a | 466 | after a comma, it will apply to writes only. In other words, |
d9472271 JA |
467 | the format is either bs=read_and_write or bs=read,write,trim. |
468 | bs=4k,8k will thus use 4k blocks for reads, 8k blocks for | |
469 | writes, and 8k for trims. You can terminate the list with | |
470 | a trailing comma. bs=4k,8k, would use the default value for | |
471 | trims.. If you only wish to set the write size, you | |
787f7e95 JA |
472 | can do so by passing an empty read size - bs=,8k will set |
473 | 8k for writes and leave the read default value. | |
a00735e6 | 474 | |
2b7a01d0 JA |
475 | blockalign=int |
476 | ba=int At what boundary to align random IO offsets. Defaults to | |
477 | the same as 'blocksize' the minimum blocksize given. | |
478 | Minimum alignment is typically 512b for using direct IO, | |
479 | though it usually depends on the hardware block size. This | |
480 | option is mutually exclusive with using a random map for | |
481 | files, so it will turn off that option. | |
482 | ||
d3aad8f2 | 483 | blocksize_range=irange |
71bfa161 JA |
484 | bsrange=irange Instead of giving a single block size, specify a range |
485 | and fio will mix the issued io block sizes. The issued | |
486 | io unit will always be a multiple of the minimum value | |
f90eff5a JA |
487 | given (also see bs_unaligned). Applies to both reads and |
488 | writes, however a second range can be given after a comma. | |
489 | See bs=. | |
a00735e6 | 490 | |
564ca972 JA |
491 | bssplit=str Sometimes you want even finer grained control of the |
492 | block sizes issued, not just an even split between them. | |
493 | This option allows you to weight various block sizes, | |
494 | so that you are able to define a specific amount of | |
495 | block sizes issued. The format for this option is: | |
496 | ||
497 | bssplit=blocksize/percentage:blocksize/percentage | |
498 | ||
499 | for as many block sizes as needed. So if you want to define | |
500 | a workload that has 50% 64k blocks, 10% 4k blocks, and | |
501 | 40% 32k blocks, you would write: | |
502 | ||
503 | bssplit=4k/10:64k/50:32k/40 | |
504 | ||
505 | Ordering does not matter. If the percentage is left blank, | |
506 | fio will fill in the remaining values evenly. So a bssplit | |
507 | option like this one: | |
508 | ||
509 | bssplit=4k/50:1k/:32k/ | |
510 | ||
511 | would have 50% 4k ios, and 25% 1k and 32k ios. The percentages | |
512 | always add up to 100, if bssplit is given a range that adds | |
513 | up to more, it will error out. | |
514 | ||
720e84ad JA |
515 | bssplit also supports giving separate splits to reads and |
516 | writes. The format is identical to what bs= accepts. You | |
517 | have to separate the read and write parts with a comma. So | |
518 | if you want a workload that has 50% 2k reads and 50% 4k reads, | |
519 | while having 90% 4k writes and 10% 8k writes, you would | |
520 | specify: | |
521 | ||
522 | bssplit=2k/50:4k/50,4k/90,8k/10 | |
523 | ||
d3aad8f2 | 524 | blocksize_unaligned |
690adba3 JA |
525 | bs_unaligned If this option is given, any byte size value within bsrange |
526 | may be used as a block range. This typically wont work with | |
527 | direct IO, as that normally requires sector alignment. | |
71bfa161 | 528 | |
6aca9b3d JA |
529 | bs_is_seq_rand If this option is set, fio will use the normal read,write |
530 | blocksize settings as sequential,random instead. Any random | |
531 | read or write will use the WRITE blocksize settings, and any | |
532 | sequential read or write will use the READ blocksize setting. | |
533 | ||
e9459e5a JA |
534 | zero_buffers If this option is given, fio will init the IO buffers to |
535 | all zeroes. The default is to fill them with random data. | |
7750aac4 JA |
536 | The resulting IO buffers will not be completely zeroed, |
537 | unless scramble_buffers is also turned off. | |
e9459e5a | 538 | |
5973cafb JA |
539 | refill_buffers If this option is given, fio will refill the IO buffers |
540 | on every submit. The default is to only fill it at init | |
541 | time and reuse that data. Only makes sense if zero_buffers | |
41ccd845 JA |
542 | isn't specified, naturally. If data verification is enabled, |
543 | refill_buffers is also automatically enabled. | |
5973cafb | 544 | |
fd68418e JA |
545 | scramble_buffers=bool If refill_buffers is too costly and the target is |
546 | using data deduplication, then setting this option will | |
547 | slightly modify the IO buffer contents to defeat normal | |
548 | de-dupe attempts. This is not enough to defeat more clever | |
549 | block compression attempts, but it will stop naive dedupe of | |
550 | blocks. Default: true. | |
551 | ||
c5751c62 JA |
552 | buffer_compress_percentage=int If this is set, then fio will attempt to |
553 | provide IO buffer content (on WRITEs) that compress to | |
554 | the specified level. Fio does this by providing a mix of | |
555 | random data and zeroes. Note that this is per block size | |
556 | unit, for file/disk wide compression level that matches | |
557 | this setting, you'll also want to set refill_buffers. | |
558 | ||
559 | buffer_compress_chunk=int See buffer_compress_percentage. This | |
560 | setting allows fio to manage how big the ranges of random | |
561 | data and zeroed data is. Without this set, fio will | |
562 | provide buffer_compress_percentage of blocksize random | |
563 | data, followed by the remaining zeroed. With this set | |
564 | to some chunk size smaller than the block size, fio can | |
565 | alternate random and zeroed data throughout the IO | |
566 | buffer. | |
567 | ||
5c94b008 JA |
568 | buffer_pattern=str If set, fio will fill the io buffers with this |
569 | pattern. If not set, the contents of io buffers is defined by | |
570 | the other options related to buffer contents. The setting can | |
571 | be any pattern of bytes, and can be prefixed with 0x for hex | |
572 | values. It may also be a string, where the string must then | |
573 | be wrapped with "". | |
574 | ||
575 | dedupe_percentage=int If set, fio will generate this percentage of | |
576 | identical buffers when writing. These buffers will be | |
577 | naturally dedupable. The contents of the buffers depend on | |
578 | what other buffer compression settings have been set. It's | |
579 | possible to have the individual buffers either fully | |
580 | compressible, or not at all. This option only controls the | |
581 | distribution of unique buffers. | |
ce35b1ec | 582 | |
71bfa161 JA |
583 | nrfiles=int Number of files to use for this job. Defaults to 1. |
584 | ||
390b1537 JA |
585 | openfiles=int Number of files to keep open at the same time. Defaults to |
586 | the same as nrfiles, can be set smaller to limit the number | |
587 | simultaneous opens. | |
588 | ||
5af1c6f3 JA |
589 | file_service_type=str Defines how fio decides which file from a job to |
590 | service next. The following types are defined: | |
591 | ||
592 | random Just choose a file at random. | |
593 | ||
594 | roundrobin Round robin over open files. This | |
595 | is the default. | |
596 | ||
a086c257 JA |
597 | sequential Finish one file before moving on to |
598 | the next. Multiple files can still be | |
599 | open depending on 'openfiles'. | |
600 | ||
1907dbc6 JA |
601 | The string can have a number appended, indicating how |
602 | often to switch to a new file. So if option random:4 is | |
603 | given, fio will switch to a new random file after 4 ios | |
604 | have been issued. | |
605 | ||
71bfa161 JA |
606 | ioengine=str Defines how the job issues io to the file. The following |
607 | types are defined: | |
608 | ||
609 | sync Basic read(2) or write(2) io. lseek(2) is | |
610 | used to position the io location. | |
611 | ||
a31041ea | 612 | psync Basic pread(2) or pwrite(2) io. |
613 | ||
e05af9e5 | 614 | vsync Basic readv(2) or writev(2) IO. |
1d2af02a | 615 | |
a46c5e01 JA |
616 | psyncv Basic preadv(2) or pwritev(2) IO. |
617 | ||
15d182aa JA |
618 | libaio Linux native asynchronous io. Note that Linux |
619 | may only support queued behaviour with | |
620 | non-buffered IO (set direct=1 or buffered=0). | |
de890a1e | 621 | This engine defines engine specific options. |
71bfa161 JA |
622 | |
623 | posixaio glibc posix asynchronous io. | |
624 | ||
417f0068 JA |
625 | solarisaio Solaris native asynchronous io. |
626 | ||
03e20d68 BC |
627 | windowsaio Windows native asynchronous io. |
628 | ||
71bfa161 JA |
629 | mmap File is memory mapped and data copied |
630 | to/from using memcpy(3). | |
631 | ||
632 | splice splice(2) is used to transfer the data and | |
633 | vmsplice(2) to transfer data from user | |
634 | space to the kernel. | |
635 | ||
d0ff85df JA |
636 | syslet-rw Use the syslet system calls to make |
637 | regular read/write async. | |
638 | ||
71bfa161 | 639 | sg SCSI generic sg v3 io. May either be |
6c219763 | 640 | synchronous using the SG_IO ioctl, or if |
71bfa161 JA |
641 | the target is an sg character device |
642 | we use read(2) and write(2) for asynchronous | |
643 | io. | |
644 | ||
a94ea28b JA |
645 | null Doesn't transfer any data, just pretends |
646 | to. This is mainly used to exercise fio | |
647 | itself and for debugging/testing purposes. | |
648 | ||
ed92ac0c | 649 | net Transfer over the network to given host:port. |
de890a1e SL |
650 | Depending on the protocol used, the hostname, |
651 | port, listen and filename options are used to | |
652 | specify what sort of connection to make, while | |
653 | the protocol option determines which protocol | |
654 | will be used. | |
655 | This engine defines engine specific options. | |
ed92ac0c | 656 | |
9cce02e8 JA |
657 | netsplice Like net, but uses splice/vmsplice to |
658 | map data and send/receive. | |
de890a1e | 659 | This engine defines engine specific options. |
9cce02e8 | 660 | |
53aec0a4 | 661 | cpuio Doesn't transfer any data, but burns CPU |
ba0fbe10 JA |
662 | cycles according to the cpuload= and |
663 | cpucycle= options. Setting cpuload=85 | |
664 | will cause that job to do nothing but burn | |
36ecec83 GP |
665 | 85% of the CPU. In case of SMP machines, |
666 | use numjobs=<no_of_cpu> to get desired CPU | |
667 | usage, as the cpuload only loads a single | |
668 | CPU at the desired rate. | |
ba0fbe10 | 669 | |
e9a1806f JA |
670 | guasi The GUASI IO engine is the Generic Userspace |
671 | Asyncronous Syscall Interface approach | |
672 | to async IO. See | |
673 | ||
674 | http://www.xmailserver.org/guasi-lib.html | |
675 | ||
676 | for more info on GUASI. | |
677 | ||
21b8aee8 | 678 | rdma The RDMA I/O engine supports both RDMA |
eb52fa3f BVA |
679 | memory semantics (RDMA_WRITE/RDMA_READ) and |
680 | channel semantics (Send/Recv) for the | |
681 | InfiniBand, RoCE and iWARP protocols. | |
21b8aee8 | 682 | |
b861be9f JA |
683 | falloc IO engine that does regular fallocate to |
684 | simulate data transfer as fio ioengine. | |
685 | DDIR_READ does fallocate(,mode = keep_size,) | |
686 | DDIR_WRITE does fallocate(,mode = 0) | |
687 | DDIR_TRIM does fallocate(,mode = punch_hole) | |
d54fce84 DM |
688 | |
689 | e4defrag IO engine that does regular EXT4_IOC_MOVE_EXT | |
b861be9f JA |
690 | ioctls to simulate defragment activity in |
691 | request to DDIR_WRITE event | |
692 | ||
693 | rbd IO engine supporting direct access to Ceph | |
694 | Rados Block Devices (RBD) via librbd without | |
695 | the need to use the kernel rbd driver. This | |
696 | ioengine defines engine specific options. | |
697 | ||
698 | gfapi Using Glusterfs libgfapi sync interface to | |
699 | direct access to Glusterfs volumes without | |
700 | options. | |
701 | ||
702 | gfapi_async Using Glusterfs libgfapi async interface | |
703 | to direct access to Glusterfs volumes without | |
704 | having to go through FUSE. This ioengine | |
705 | defines engine specific options. | |
0981fd71 | 706 | |
b74e419e MM |
707 | libhdfs Read and write through Hadoop (HDFS). |
708 | The 'filename' option is used to specify host, | |
709 | port of the hdfs name-node to connect. This | |
710 | engine interprets offsets a little | |
711 | differently. In HDFS, files once created | |
712 | cannot be modified. So random writes are not | |
713 | possible. To imitate this, libhdfs engine | |
714 | expects bunch of small files to be created | |
715 | over HDFS, and engine will randomly pick a | |
716 | file out of those files based on the offset | |
717 | generated by fio backend. (see the example | |
718 | job file to create such files, use rw=write | |
719 | option). Please note, you might want to set | |
720 | necessary environment variables to work with | |
721 | hdfs/libhdfs properly. | |
1b10477b | 722 | |
8a7bd877 JA |
723 | external Prefix to specify loading an external |
724 | IO engine object file. Append the engine | |
725 | filename, eg ioengine=external:/tmp/foo.o | |
726 | to load ioengine foo.o in /tmp. | |
727 | ||
71bfa161 JA |
728 | iodepth=int This defines how many io units to keep in flight against |
729 | the file. The default is 1 for each file defined in this | |
730 | job, can be overridden with a larger value for higher | |
ee72ca09 JA |
731 | concurrency. Note that increasing iodepth beyond 1 will not |
732 | affect synchronous ioengines (except for small degress when | |
9b836561 | 733 | verify_async is in use). Even async engines may impose OS |
ee72ca09 JA |
734 | restrictions causing the desired depth not to be achieved. |
735 | This may happen on Linux when using libaio and not setting | |
736 | direct=1, since buffered IO is not async on that OS. Keep an | |
737 | eye on the IO depth distribution in the fio output to verify | |
738 | that the achieved depth is as expected. Default: 1. | |
71bfa161 | 739 | |
4950421a | 740 | iodepth_batch_submit=int |
cb5ab512 | 741 | iodepth_batch=int This defines how many pieces of IO to submit at once. |
89e820f6 JA |
742 | It defaults to 1 which means that we submit each IO |
743 | as soon as it is available, but can be raised to submit | |
744 | bigger batches of IO at the time. | |
cb5ab512 | 745 | |
4950421a JA |
746 | iodepth_batch_complete=int This defines how many pieces of IO to retrieve |
747 | at once. It defaults to 1 which means that we'll ask | |
748 | for a minimum of 1 IO in the retrieval process from | |
749 | the kernel. The IO retrieval will go on until we | |
750 | hit the limit set by iodepth_low. If this variable is | |
751 | set to 0, then fio will always check for completed | |
752 | events before queuing more IO. This helps reduce | |
753 | IO latency, at the cost of more retrieval system calls. | |
754 | ||
e916b390 JA |
755 | iodepth_low=int The low water mark indicating when to start filling |
756 | the queue again. Defaults to the same as iodepth, meaning | |
757 | that fio will attempt to keep the queue full at all times. | |
758 | If iodepth is set to eg 16 and iodepth_low is set to 4, then | |
759 | after fio has filled the queue of 16 requests, it will let | |
760 | the depth drain down to 4 before starting to fill it again. | |
761 | ||
71bfa161 | 762 | direct=bool If value is true, use non-buffered io. This is usually |
9b836561 | 763 | O_DIRECT. Note that ZFS on Solaris doesn't support direct io. |
93bcfd20 | 764 | On Windows the synchronous ioengines don't support direct io. |
76a43db4 | 765 | |
d01612f3 CM |
766 | atomic=bool If value is true, attempt to use atomic direct IO. Atomic |
767 | writes are guaranteed to be stable once acknowledged by | |
768 | the operating system. Only Linux supports O_ATOMIC right | |
769 | now. | |
770 | ||
76a43db4 JA |
771 | buffered=bool If value is true, use buffered io. This is the opposite |
772 | of the 'direct' option. Defaults to true. | |
71bfa161 | 773 | |
f7fa2653 | 774 | offset=int Start io at the given offset in the file. The data before |
71bfa161 JA |
775 | the given offset will not be touched. This effectively |
776 | caps the file size at real_size - offset. | |
777 | ||
214ac7e0 | 778 | offset_increment=int If this is provided, then the real offset becomes |
69bdd6ba JH |
779 | offset + offset_increment * thread_number, where the thread |
780 | number is a counter that starts at 0 and is incremented for | |
781 | each sub-job (i.e. when numjobs option is specified). This | |
782 | option is useful if there are several jobs which are intended | |
783 | to operate on a file in parallel disjoint segments, with | |
784 | even spacing between the starting points. | |
214ac7e0 | 785 | |
ddf24e42 JA |
786 | number_ios=int Fio will normally perform IOs until it has exhausted the size |
787 | of the region set by size=, or if it exhaust the allocated | |
788 | time (or hits an error condition). With this setting, the | |
789 | range/size can be set independently of the number of IOs to | |
790 | perform. When fio reaches this number, it will exit normally | |
791 | and report status. | |
792 | ||
71bfa161 JA |
793 | fsync=int If writing to a file, issue a sync of the dirty data |
794 | for every number of blocks given. For example, if you give | |
795 | 32 as a parameter, fio will sync the file for every 32 | |
796 | writes issued. If fio is using non-buffered io, we may | |
797 | not sync the file. The exception is the sg io engine, which | |
6c219763 | 798 | synchronizes the disk cache anyway. |
71bfa161 | 799 | |
e76b1da4 | 800 | fdatasync=int Like fsync= but uses fdatasync() to only sync data and not |
5f9099ea | 801 | metadata blocks. |
93bcfd20 | 802 | In FreeBSD and Windows there is no fdatasync(), this falls back to |
e72fa4d4 | 803 | using fsync() |
5f9099ea | 804 | |
e76b1da4 JA |
805 | sync_file_range=str:val Use sync_file_range() for every 'val' number of |
806 | write operations. Fio will track range of writes that | |
807 | have happened since the last sync_file_range() call. 'str' | |
808 | can currently be one or more of: | |
809 | ||
810 | wait_before SYNC_FILE_RANGE_WAIT_BEFORE | |
811 | write SYNC_FILE_RANGE_WRITE | |
812 | wait_after SYNC_FILE_RANGE_WAIT_AFTER | |
813 | ||
814 | So if you do sync_file_range=wait_before,write:8, fio would | |
815 | use SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE for | |
816 | every 8 writes. Also see the sync_file_range(2) man page. | |
817 | This option is Linux specific. | |
818 | ||
5036fc1e JA |
819 | overwrite=bool If true, writes to a file will always overwrite existing |
820 | data. If the file doesn't already exist, it will be | |
821 | created before the write phase begins. If the file exists | |
822 | and is large enough for the specified write phase, nothing | |
823 | will be done. | |
71bfa161 | 824 | |
dbd11ead | 825 | end_fsync=bool If true, fsync file contents when a write stage has completed. |
71bfa161 | 826 | |
ebb1415f JA |
827 | fsync_on_close=bool If true, fio will fsync() a dirty file on close. |
828 | This differs from end_fsync in that it will happen on every | |
829 | file close, not just at the end of the job. | |
830 | ||
71bfa161 JA |
831 | rwmixread=int How large a percentage of the mix should be reads. |
832 | ||
833 | rwmixwrite=int How large a percentage of the mix should be writes. If both | |
834 | rwmixread and rwmixwrite is given and the values do not add | |
835 | up to 100%, the latter of the two will be used to override | |
c35dd7a6 JA |
836 | the first. This may interfere with a given rate setting, |
837 | if fio is asked to limit reads or writes to a certain rate. | |
838 | If that is the case, then the distribution may be skewed. | |
71bfa161 | 839 | |
92d42d69 JA |
840 | random_distribution=str:float By default, fio will use a completely uniform |
841 | random distribution when asked to perform random IO. Sometimes | |
842 | it is useful to skew the distribution in specific ways, | |
843 | ensuring that some parts of the data is more hot than others. | |
844 | fio includes the following distribution models: | |
845 | ||
846 | random Uniform random distribution | |
847 | zipf Zipf distribution | |
848 | pareto Pareto distribution | |
849 | ||
850 | When using a zipf or pareto distribution, an input value | |
851 | is also needed to define the access pattern. For zipf, this | |
852 | is the zipf theta. For pareto, it's the pareto power. Fio | |
853 | includes a test program, genzipf, that can be used visualize | |
854 | what the given input values will yield in terms of hit rates. | |
855 | If you wanted to use zipf with a theta of 1.2, you would use | |
856 | random_distribution=zipf:1.2 as the option. If a non-uniform | |
857 | model is used, fio will disable use of the random map. | |
858 | ||
211c9b89 JA |
859 | percentage_random=int For a random workload, set how big a percentage should |
860 | be random. This defaults to 100%, in which case the workload | |
861 | is fully random. It can be set from anywhere from 0 to 100. | |
862 | Setting it to 0 would make the workload fully sequential. Any | |
863 | setting in between will result in a random mix of sequential | |
d9472271 JA |
864 | and random IO, at the given percentages. It is possible to |
865 | set different values for reads, writes, and trim. To do so, | |
866 | simply use a comma separated list. See blocksize. | |
211c9b89 | 867 | |
bb8895e0 JA |
868 | norandommap Normally fio will cover every block of the file when doing |
869 | random IO. If this option is given, fio will just get a | |
870 | new random offset without looking at past io history. This | |
871 | means that some blocks may not be read or written, and that | |
872 | some blocks may be read/written more than once. This option | |
8347239a JA |
873 | is mutually exclusive with verify= if and only if multiple |
874 | blocksizes (via bsrange=) are used, since fio only tracks | |
875 | complete rewrites of blocks. | |
bb8895e0 | 876 | |
0408c206 JA |
877 | softrandommap=bool See norandommap. If fio runs with the random block map |
878 | enabled and it fails to allocate the map, if this option is | |
879 | set it will continue without a random block map. As coverage | |
880 | will not be as complete as with random maps, this option is | |
2b386d25 JA |
881 | disabled by default. |
882 | ||
e8b1961d JA |
883 | random_generator=str Fio supports the following engines for generating |
884 | IO offsets for random IO: | |
885 | ||
886 | tausworthe Strong 2^88 cycle random number generator | |
887 | lfsr Linear feedback shift register generator | |
888 | ||
889 | Tausworthe is a strong random number generator, but it | |
890 | requires tracking on the side if we want to ensure that | |
891 | blocks are only read or written once. LFSR guarantees | |
892 | that we never generate the same offset twice, and it's | |
893 | also less computationally expensive. It's not a true | |
894 | random generator, however, though for IO purposes it's | |
895 | typically good enough. LFSR only works with single | |
896 | block sizes, not with workloads that use multiple block | |
897 | sizes. If used with such a workload, fio may read or write | |
898 | some blocks multiple times. | |
43f09da1 | 899 | |
71bfa161 JA |
900 | nice=int Run the job with the given nice value. See man nice(2). |
901 | ||
902 | prio=int Set the io priority value of this job. Linux limits us to | |
903 | a positive value between 0 and 7, with 0 being the highest. | |
904 | See man ionice(1). | |
905 | ||
906 | prioclass=int Set the io priority class. See man ionice(1). | |
907 | ||
908 | thinktime=int Stall the job x microseconds after an io has completed before | |
909 | issuing the next. May be used to simulate processing being | |
48097d5c JA |
910 | done by an application. See thinktime_blocks and |
911 | thinktime_spin. | |
912 | ||
913 | thinktime_spin=int | |
914 | Only valid if thinktime is set - pretend to spend CPU time | |
915 | doing something with the data received, before falling back | |
916 | to sleeping for the rest of the period specified by | |
917 | thinktime. | |
9c1f7434 | 918 | |
4d01ece6 | 919 | thinktime_blocks=int |
9c1f7434 JA |
920 | Only valid if thinktime is set - control how many blocks |
921 | to issue, before waiting 'thinktime' usecs. If not set, | |
922 | defaults to 1 which will make fio wait 'thinktime' usecs | |
4d01ece6 JA |
923 | after every block. This effectively makes any queue depth |
924 | setting redundant, since no more than 1 IO will be queued | |
925 | before we have to complete it and do our thinktime. In | |
926 | other words, this setting effectively caps the queue depth | |
927 | if the latter is larger. | |
71bfa161 | 928 | |
581e7141 | 929 | rate=int Cap the bandwidth used by this job. The number is in bytes/sec, |
b09da8fa | 930 | the normal suffix rules apply. You can use rate=500k to limit |
581e7141 JA |
931 | reads and writes to 500k each, or you can specify read and |
932 | writes separately. Using rate=1m,500k would limit reads to | |
933 | 1MB/sec and writes to 500KB/sec. Capping only reads or | |
934 | writes can be done with rate=,500k or rate=500k,. The former | |
935 | will only limit writes (to 500KB/sec), the latter will only | |
936 | limit reads. | |
71bfa161 JA |
937 | |
938 | ratemin=int Tell fio to do whatever it can to maintain at least this | |
4e991c23 | 939 | bandwidth. Failing to meet this requirement, will cause |
581e7141 JA |
940 | the job to exit. The same format as rate is used for |
941 | read vs write separation. | |
4e991c23 JA |
942 | |
943 | rate_iops=int Cap the bandwidth to this number of IOPS. Basically the same | |
944 | as rate, just specified independently of bandwidth. If the | |
945 | job is given a block size range instead of a fixed value, | |
581e7141 | 946 | the smallest block size is used as the metric. The same format |
de8f6de9 | 947 | as rate is used for read vs write separation. |
4e991c23 JA |
948 | |
949 | rate_iops_min=int If fio doesn't meet this rate of IO, it will cause | |
581e7141 | 950 | the job to exit. The same format as rate is used for read vs |
de8f6de9 | 951 | write separation. |
71bfa161 | 952 | |
3e260a46 JA |
953 | latency_target=int If set, fio will attempt to find the max performance |
954 | point that the given workload will run at while maintaining a | |
955 | latency below this target. The values is given in microseconds. | |
956 | See latency_window and latency_percentile | |
957 | ||
958 | latency_window=int Used with latency_target to specify the sample window | |
959 | that the job is run at varying queue depths to test the | |
960 | performance. The value is given in microseconds. | |
961 | ||
962 | latency_percentile=float The percentage of IOs that must fall within the | |
963 | criteria specified by latency_target and latency_window. If not | |
964 | set, this defaults to 100.0, meaning that all IOs must be equal | |
965 | or below to the value set by latency_target. | |
966 | ||
15501535 JA |
967 | max_latency=int If set, fio will exit the job if it exceeds this maximum |
968 | latency. It will exit with an ETIME error. | |
969 | ||
71bfa161 | 970 | ratecycle=int Average bandwidth for 'rate' and 'ratemin' over this number |
6c219763 | 971 | of milliseconds. |
71bfa161 JA |
972 | |
973 | cpumask=int Set the CPU affinity of this job. The parameter given is a | |
a08bc17f JA |
974 | bitmask of allowed CPU's the job may run on. So if you want |
975 | the allowed CPUs to be 1 and 5, you would pass the decimal | |
976 | value of (1 << 1 | 1 << 5), or 34. See man | |
7dbb6eba | 977 | sched_setaffinity(2). This may not work on all supported |
b0ea08ce JA |
978 | operating systems or kernel versions. This option doesn't |
979 | work well for a higher CPU count than what you can store in | |
980 | an integer mask, so it can only control cpus 1-32. For | |
981 | boxes with larger CPU counts, use cpus_allowed. | |
71bfa161 | 982 | |
d2e268b0 JA |
983 | cpus_allowed=str Controls the same options as cpumask, but it allows a text |
984 | setting of the permitted CPUs instead. So to use CPUs 1 and | |
62a7273d JA |
985 | 5, you would specify cpus_allowed=1,5. This options also |
986 | allows a range of CPUs. Say you wanted a binding to CPUs | |
987 | 1, 5, and 8-15, you would set cpus_allowed=1,5,8-15. | |
d2e268b0 | 988 | |
c2acfbac JA |
989 | cpus_allowed_policy=str Set the policy of how fio distributes the CPUs |
990 | specified by cpus_allowed or cpumask. Two policies are | |
991 | supported: | |
992 | ||
993 | shared All jobs will share the CPU set specified. | |
994 | split Each job will get a unique CPU from the CPU set. | |
995 | ||
996 | 'shared' is the default behaviour, if the option isn't | |
ada083cd JA |
997 | specified. If split is specified, then fio will will assign |
998 | one cpu per job. If not enough CPUs are given for the jobs | |
999 | listed, then fio will roundrobin the CPUs in the set. | |
c2acfbac | 1000 | |
d0b937ed YR |
1001 | numa_cpu_nodes=str Set this job running on spcified NUMA nodes' CPUs. The |
1002 | arguments allow comma delimited list of cpu numbers, | |
1003 | A-B ranges, or 'all'. Note, to enable numa options support, | |
67bf9823 | 1004 | fio must be built on a system with libnuma-dev(el) installed. |
d0b937ed YR |
1005 | |
1006 | numa_mem_policy=str Set this job's memory policy and corresponding NUMA | |
1007 | nodes. Format of the argements: | |
1008 | <mode>[:<nodelist>] | |
1009 | `mode' is one of the following memory policy: | |
1010 | default, prefer, bind, interleave, local | |
1011 | For `default' and `local' memory policy, no node is | |
1012 | needed to be specified. | |
1013 | For `prefer', only one node is allowed. | |
1014 | For `bind' and `interleave', it allow comma delimited | |
1015 | list of numbers, A-B ranges, or 'all'. | |
1016 | ||
e417fd66 | 1017 | startdelay=time Start this job the specified number of seconds after fio |
71bfa161 JA |
1018 | has started. Only useful if the job file contains several |
1019 | jobs, and you want to delay starting some jobs to a certain | |
1020 | time. | |
1021 | ||
e417fd66 | 1022 | runtime=time Tell fio to terminate processing after the specified number |
71bfa161 JA |
1023 | of seconds. It can be quite hard to determine for how long |
1024 | a specified job will run, so this parameter is handy to | |
1025 | cap the total runtime to a given time. | |
1026 | ||
cf4464ca | 1027 | time_based If set, fio will run for the duration of the runtime |
bf9a3edb | 1028 | specified even if the file(s) are completely read or |
cf4464ca JA |
1029 | written. It will simply loop over the same workload |
1030 | as many times as the runtime allows. | |
1031 | ||
e417fd66 | 1032 | ramp_time=time If set, fio will run the specified workload for this amount |
721938ae JA |
1033 | of time before logging any performance numbers. Useful for |
1034 | letting performance settle before logging results, thus | |
b29ee5b3 JA |
1035 | minimizing the runtime required for stable results. Note |
1036 | that the ramp_time is considered lead in time for a job, | |
1037 | thus it will increase the total runtime if a special timeout | |
1038 | or runtime is specified. | |
721938ae | 1039 | |
71bfa161 JA |
1040 | invalidate=bool Invalidate the buffer/page cache parts for this file prior |
1041 | to starting io. Defaults to true. | |
1042 | ||
1043 | sync=bool Use sync io for buffered writes. For the majority of the | |
1044 | io engines, this means using O_SYNC. | |
1045 | ||
d3aad8f2 | 1046 | iomem=str |
71bfa161 JA |
1047 | mem=str Fio can use various types of memory as the io unit buffer. |
1048 | The allowed values are: | |
1049 | ||
1050 | malloc Use memory from malloc(3) as the buffers. | |
1051 | ||
1052 | shm Use shared memory as the buffers. Allocated | |
1053 | through shmget(2). | |
1054 | ||
74b025b0 JA |
1055 | shmhuge Same as shm, but use huge pages as backing. |
1056 | ||
313cb206 JA |
1057 | mmap Use mmap to allocate buffers. May either be |
1058 | anonymous memory, or can be file backed if | |
1059 | a filename is given after the option. The | |
1060 | format is mem=mmap:/path/to/file. | |
71bfa161 | 1061 | |
d0bdaf49 JA |
1062 | mmaphuge Use a memory mapped huge file as the buffer |
1063 | backing. Append filename after mmaphuge, ala | |
1064 | mem=mmaphuge:/hugetlbfs/file | |
1065 | ||
71bfa161 | 1066 | The area allocated is a function of the maximum allowed |
5394ae5f JA |
1067 | bs size for the job, multiplied by the io depth given. Note |
1068 | that for shmhuge and mmaphuge to work, the system must have | |
1069 | free huge pages allocated. This can normally be checked | |
1070 | and set by reading/writing /proc/sys/vm/nr_hugepages on a | |
b22989b9 | 1071 | Linux system. Fio assumes a huge page is 4MB in size. So |
5394ae5f JA |
1072 | to calculate the number of huge pages you need for a given |
1073 | job file, add up the io depth of all jobs (normally one unless | |
1074 | iodepth= is used) and multiply by the maximum bs set. Then | |
1075 | divide that number by the huge page size. You can see the | |
1076 | size of the huge pages in /proc/meminfo. If no huge pages | |
1077 | are allocated by having a non-zero number in nr_hugepages, | |
56bb17f2 | 1078 | using mmaphuge or shmhuge will fail. Also see hugepage-size. |
5394ae5f JA |
1079 | |
1080 | mmaphuge also needs to have hugetlbfs mounted and the file | |
1081 | location should point there. So if it's mounted in /huge, | |
1082 | you would use mem=mmaphuge:/huge/somefile. | |
71bfa161 | 1083 | |
d529ee19 JA |
1084 | iomem_align=int This indiciates the memory alignment of the IO memory buffers. |
1085 | Note that the given alignment is applied to the first IO unit | |
1086 | buffer, if using iodepth the alignment of the following buffers | |
1087 | are given by the bs used. In other words, if using a bs that is | |
1088 | a multiple of the page sized in the system, all buffers will | |
1089 | be aligned to this value. If using a bs that is not page | |
1090 | aligned, the alignment of subsequent IO memory buffers is the | |
1091 | sum of the iomem_align and bs used. | |
1092 | ||
f7fa2653 | 1093 | hugepage-size=int |
56bb17f2 | 1094 | Defines the size of a huge page. Must at least be equal |
b22989b9 | 1095 | to the system setting, see /proc/meminfo. Defaults to 4MB. |
c51074e7 JA |
1096 | Should probably always be a multiple of megabytes, so using |
1097 | hugepage-size=Xm is the preferred way to set this to avoid | |
1098 | setting a non-pow-2 bad value. | |
56bb17f2 | 1099 | |
71bfa161 JA |
1100 | exitall When one job finishes, terminate the rest. The default is |
1101 | to wait for each job to finish, sometimes that is not the | |
1102 | desired action. | |
1103 | ||
1104 | bwavgtime=int Average the calculated bandwidth over the given time. Value | |
6c219763 | 1105 | is specified in milliseconds. |
71bfa161 | 1106 | |
c8eeb9df JA |
1107 | iopsavgtime=int Average the calculated IOPS over the given time. Value |
1108 | is specified in milliseconds. | |
1109 | ||
71bfa161 JA |
1110 | create_serialize=bool If true, serialize the file creating for the jobs. |
1111 | This may be handy to avoid interleaving of data | |
1112 | files, which may greatly depend on the filesystem | |
1113 | used and even the number of processors in the system. | |
1114 | ||
1115 | create_fsync=bool fsync the data file after creation. This is the | |
1116 | default. | |
1117 | ||
814452bd JA |
1118 | create_on_open=bool Don't pre-setup the files for IO, just create open() |
1119 | when it's time to do IO to that file. | |
1120 | ||
25460cf6 JA |
1121 | create_only=bool If true, fio will only run the setup phase of the job. |
1122 | If files need to be laid out or updated on disk, only | |
1123 | that will be done. The actual job contents are not | |
1124 | executed. | |
1125 | ||
afad68f7 | 1126 | pre_read=bool If this is given, files will be pre-read into memory before |
34f1c044 JA |
1127 | starting the given IO operation. This will also clear |
1128 | the 'invalidate' flag, since it is pointless to pre-read | |
9c0d2241 JA |
1129 | and then drop the cache. This will only work for IO engines |
1130 | that are seekable, since they allow you to read the same data | |
1131 | multiple times. Thus it will not work on eg network or splice | |
1132 | IO. | |
afad68f7 | 1133 | |
e545a6ce | 1134 | unlink=bool Unlink the job files when done. Not the default, as repeated |
bf9a3edb JA |
1135 | runs of that job would then waste time recreating the file |
1136 | set again and again. | |
71bfa161 JA |
1137 | |
1138 | loops=int Run the specified number of iterations of this job. Used | |
1139 | to repeat the same workload a given number of times. Defaults | |
1140 | to 1. | |
1141 | ||
62167762 JC |
1142 | verify_only Do not perform specified workload---only verify data still |
1143 | matches previous invocation of this workload. This option | |
1144 | allows one to check data multiple times at a later date | |
1145 | without overwriting it. This option makes sense only for | |
1146 | workloads that write data, and does not support workloads | |
1147 | with the time_based option set. | |
1148 | ||
68e1f29a | 1149 | do_verify=bool Run the verify phase after a write phase. Only makes sense if |
e84c73a8 SL |
1150 | verify is set. Defaults to 1. |
1151 | ||
71bfa161 JA |
1152 | verify=str If writing to a file, fio can verify the file contents |
1153 | after each iteration of the job. The allowed values are: | |
1154 | ||
1155 | md5 Use an md5 sum of the data area and store | |
1156 | it in the header of each block. | |
1157 | ||
17dc34df JA |
1158 | crc64 Use an experimental crc64 sum of the data |
1159 | area and store it in the header of each | |
1160 | block. | |
1161 | ||
bac39e0e JA |
1162 | crc32c Use a crc32c sum of the data area and store |
1163 | it in the header of each block. | |
1164 | ||
3845591f | 1165 | crc32c-intel Use hardware assisted crc32c calcuation |
0539d758 JA |
1166 | provided on SSE4.2 enabled processors. Falls |
1167 | back to regular software crc32c, if not | |
1168 | supported by the system. | |
3845591f | 1169 | |
71bfa161 JA |
1170 | crc32 Use a crc32 sum of the data area and store |
1171 | it in the header of each block. | |
1172 | ||
969f7ed3 JA |
1173 | crc16 Use a crc16 sum of the data area and store |
1174 | it in the header of each block. | |
1175 | ||
17dc34df JA |
1176 | crc7 Use a crc7 sum of the data area and store |
1177 | it in the header of each block. | |
1178 | ||
844ea602 JA |
1179 | xxhash Use xxhash as the checksum function. Generally |
1180 | the fastest software checksum that fio | |
1181 | supports. | |
1182 | ||
cd14cc10 JA |
1183 | sha512 Use sha512 as the checksum function. |
1184 | ||
1185 | sha256 Use sha256 as the checksum function. | |
1186 | ||
7c353ceb JA |
1187 | sha1 Use optimized sha1 as the checksum function. |
1188 | ||
7437ee87 SL |
1189 | meta Write extra information about each io |
1190 | (timestamp, block number etc.). The block | |
62167762 JC |
1191 | number is verified. The io sequence number is |
1192 | verified for workloads that write data. | |
1193 | See also verify_pattern. | |
7437ee87 | 1194 | |
36690c9b JA |
1195 | null Only pretend to verify. Useful for testing |
1196 | internals with ioengine=null, not for much | |
1197 | else. | |
1198 | ||
6c219763 | 1199 | This option can be used for repeated burn-in tests of a |
71bfa161 | 1200 | system to make sure that the written data is also |
b892dc08 JA |
1201 | correctly read back. If the data direction given is |
1202 | a read or random read, fio will assume that it should | |
1203 | verify a previously written file. If the data direction | |
1204 | includes any form of write, the verify will be of the | |
1205 | newly written data. | |
71bfa161 | 1206 | |
160b966d JA |
1207 | verifysort=bool If set, fio will sort written verify blocks when it deems |
1208 | it faster to read them back in a sorted manner. This is | |
1209 | often the case when overwriting an existing file, since | |
1210 | the blocks are already laid out in the file system. You | |
1211 | can ignore this option unless doing huge amounts of really | |
1212 | fast IO where the red-black tree sorting CPU time becomes | |
1213 | significant. | |
3f9f4e26 | 1214 | |
f7fa2653 | 1215 | verify_offset=int Swap the verification header with data somewhere else |
546a9142 SL |
1216 | in the block before writing. Its swapped back before |
1217 | verifying. | |
1218 | ||
f7fa2653 | 1219 | verify_interval=int Write the verification header at a finer granularity |
3f9f4e26 SL |
1220 | than the blocksize. It will be written for chunks the |
1221 | size of header_interval. blocksize should divide this | |
1222 | evenly. | |
90059d65 | 1223 | |
0e92f873 | 1224 | verify_pattern=str If set, fio will fill the io buffers with this |
e28218f3 SL |
1225 | pattern. Fio defaults to filling with totally random |
1226 | bytes, but sometimes it's interesting to fill with a known | |
1227 | pattern for io verification purposes. Depending on the | |
1228 | width of the pattern, fio will fill 1/2/3/4 bytes of the | |
0e92f873 RR |
1229 | buffer at the time(it can be either a decimal or a hex number). |
1230 | The verify_pattern if larger than a 32-bit quantity has to | |
996093bb JA |
1231 | be a hex number that starts with either "0x" or "0X". Use |
1232 | with verify=meta. | |
e28218f3 | 1233 | |
68e1f29a | 1234 | verify_fatal=bool Normally fio will keep checking the entire contents |
a12a3b4d JA |
1235 | before quitting on a block verification failure. If this |
1236 | option is set, fio will exit the job on the first observed | |
1237 | failure. | |
e8462bd8 | 1238 | |
b463e936 JA |
1239 | verify_dump=bool If set, dump the contents of both the original data |
1240 | block and the data block we read off disk to files. This | |
1241 | allows later analysis to inspect just what kind of data | |
ef71e317 | 1242 | corruption occurred. Off by default. |
b463e936 | 1243 | |
e8462bd8 JA |
1244 | verify_async=int Fio will normally verify IO inline from the submitting |
1245 | thread. This option takes an integer describing how many | |
1246 | async offload threads to create for IO verification instead, | |
1247 | causing fio to offload the duty of verifying IO contents | |
c85c324c JA |
1248 | to one or more separate threads. If using this offload |
1249 | option, even sync IO engines can benefit from using an | |
1250 | iodepth setting higher than 1, as it allows them to have | |
1251 | IO in flight while verifies are running. | |
e8462bd8 JA |
1252 | |
1253 | verify_async_cpus=str Tell fio to set the given CPU affinity on the | |
1254 | async IO verification threads. See cpus_allowed for the | |
1255 | format used. | |
6f87418f JA |
1256 | |
1257 | verify_backlog=int Fio will normally verify the written contents of a | |
1258 | job that utilizes verify once that job has completed. In | |
1259 | other words, everything is written then everything is read | |
1260 | back and verified. You may want to verify continually | |
1261 | instead for a variety of reasons. Fio stores the meta data | |
1262 | associated with an IO block in memory, so for large | |
1263 | verify workloads, quite a bit of memory would be used up | |
1264 | holding this meta data. If this option is enabled, fio | |
f42195a3 JA |
1265 | will write only N blocks before verifying these blocks. |
1266 | ||
6f87418f JA |
1267 | verify_backlog_batch=int Control how many blocks fio will verify |
1268 | if verify_backlog is set. If not set, will default to | |
1269 | the value of verify_backlog (meaning the entire queue | |
f42195a3 JA |
1270 | is read back and verified). If verify_backlog_batch is |
1271 | less than verify_backlog then not all blocks will be verified, | |
1272 | if verify_backlog_batch is larger than verify_backlog, some | |
1273 | blocks will be verified more than once. | |
66c098b8 | 1274 | |
d392365e | 1275 | stonewall |
de8f6de9 | 1276 | wait_for_previous Wait for preceding jobs in the job file to exit, before |
71bfa161 | 1277 | starting this one. Can be used to insert serialization |
b3d62a75 JA |
1278 | points in the job file. A stone wall also implies starting |
1279 | a new reporting group. | |
1280 | ||
abcab6af | 1281 | new_group Start a new reporting group. See: group_reporting. |
71bfa161 JA |
1282 | |
1283 | numjobs=int Create the specified number of clones of this job. May be | |
1284 | used to setup a larger number of threads/processes doing | |
abcab6af AV |
1285 | the same thing. Each thread is reported separately; to see |
1286 | statistics for all clones as a whole, use group_reporting in | |
1287 | conjunction with new_group. | |
1288 | ||
1289 | group_reporting It may sometimes be interesting to display statistics for | |
04b2f799 JA |
1290 | groups of jobs as a whole instead of for each individual job. |
1291 | This is especially true if 'numjobs' is used; looking at | |
1292 | individual thread/process output quickly becomes unwieldy. | |
1293 | To see the final report per-group instead of per-job, use | |
1294 | 'group_reporting'. Jobs in a file will be part of the same | |
1295 | reporting group, unless if separated by a stonewall, or by | |
1296 | using 'new_group'. | |
71bfa161 JA |
1297 | |
1298 | thread fio defaults to forking jobs, however if this option is | |
1299 | given, fio will use pthread_create(3) to create threads | |
1300 | instead. | |
1301 | ||
f7fa2653 | 1302 | zonesize=int Divide a file into zones of the specified size. See zoneskip. |
71bfa161 | 1303 | |
f7fa2653 | 1304 | zoneskip=int Skip the specified number of bytes when zonesize data has |
71bfa161 JA |
1305 | been read. The two zone options can be used to only do |
1306 | io on zones of a file. | |
1307 | ||
076efc7c | 1308 | write_iolog=str Write the issued io patterns to the specified file. See |
5b42a488 SH |
1309 | read_iolog. Specify a separate file for each job, otherwise |
1310 | the iologs will be interspersed and the file may be corrupt. | |
71bfa161 | 1311 | |
076efc7c | 1312 | read_iolog=str Open an iolog with the specified file name and replay the |
71bfa161 | 1313 | io patterns it contains. This can be used to store a |
6df8adaa JA |
1314 | workload and replay it sometime later. The iolog given |
1315 | may also be a blktrace binary file, which allows fio | |
1316 | to replay a workload captured by blktrace. See blktrace | |
1317 | for how to capture such logging data. For blktrace replay, | |
1318 | the file needs to be turned into a blkparse binary data | |
ea3e51c3 | 1319 | file first (blkparse <device> -o /dev/null -d file_for_fio.bin). |
66c098b8 | 1320 | |
64bbb865 | 1321 | replay_no_stall=int When replaying I/O with read_iolog the default behavior |
62776229 JA |
1322 | is to attempt to respect the time stamps within the log and |
1323 | replay them with the appropriate delay between IOPS. By | |
1324 | setting this variable fio will not respect the timestamps and | |
1325 | attempt to replay them as fast as possible while still | |
1326 | respecting ordering. The result is the same I/O pattern to a | |
1327 | given device, but different timings. | |
71bfa161 | 1328 | |
d1c46c04 DN |
1329 | replay_redirect=str While replaying I/O patterns using read_iolog the |
1330 | default behavior is to replay the IOPS onto the major/minor | |
1331 | device that each IOP was recorded from. This is sometimes | |
de8f6de9 | 1332 | undesirable because on a different machine those major/minor |
d1c46c04 DN |
1333 | numbers can map to a different device. Changing hardware on |
1334 | the same system can also result in a different major/minor | |
1335 | mapping. Replay_redirect causes all IOPS to be replayed onto | |
1336 | the single specified device regardless of the device it was | |
1337 | recorded from. i.e. replay_redirect=/dev/sdc would cause all | |
1338 | IO in the blktrace to be replayed onto /dev/sdc. This means | |
1339 | multiple devices will be replayed onto a single, if the trace | |
1340 | contains multiple devices. If you want multiple devices to be | |
1341 | replayed concurrently to multiple redirected devices you must | |
1342 | blkparse your trace into separate traces and replay them with | |
1343 | independent fio invocations. Unfortuantely this also breaks | |
1344 | the strict time ordering between multiple device accesses. | |
1345 | ||
e3cedca7 | 1346 | write_bw_log=str If given, write a bandwidth log of the jobs in this job |
71bfa161 | 1347 | file. Can be used to store data of the bandwidth of the |
e0da9bc2 JA |
1348 | jobs in their lifetime. The included fio_generate_plots |
1349 | script uses gnuplot to turn these text files into nice | |
ddb754db | 1350 | graphs. See write_lat_log for behaviour of given |
8ad3b3dd JA |
1351 | filename. For this option, the suffix is _bw.x.log, where |
1352 | x is the index of the job (1..N, where N is the number of | |
1353 | jobs). | |
71bfa161 | 1354 | |
e3cedca7 | 1355 | write_lat_log=str Same as write_bw_log, except that this option stores io |
02af0988 JA |
1356 | submission, completion, and total latencies instead. If no |
1357 | filename is given with this option, the default filename of | |
1358 | "jobname_type.log" is used. Even if the filename is given, | |
1359 | fio will still append the type of log. So if one specifies | |
e3cedca7 JA |
1360 | |
1361 | write_lat_log=foo | |
1362 | ||
8ad3b3dd JA |
1363 | The actual log names will be foo_slat.x.log, foo_clat.x.log, |
1364 | and foo_lat.x.log, where x is the index of the job (1..N, | |
1365 | where N is the number of jobs). This helps fio_generate_plot | |
1366 | fine the logs automatically. | |
71bfa161 | 1367 | |
b8bc8cba JA |
1368 | write_iops_log=str Same as write_bw_log, but writes IOPS. If no filename is |
1369 | given with this option, the default filename of | |
8ad3b3dd JA |
1370 | "jobname_type.x.log" is used,where x is the index of the job |
1371 | (1..N, where N is the number of jobs). Even if the filename | |
1372 | is given, fio will still append the type of log. | |
b8bc8cba JA |
1373 | |
1374 | log_avg_msec=int By default, fio will log an entry in the iops, latency, | |
1375 | or bw log for every IO that completes. When writing to the | |
1376 | disk log, that can quickly grow to a very large size. Setting | |
1377 | this option makes fio average the each log entry over the | |
1378 | specified period of time, reducing the resolution of the log. | |
1379 | Defaults to 0. | |
1380 | ||
ae588852 JA |
1381 | log_offset=int If this is set, the iolog options will include the byte |
1382 | offset for the IO entry as well as the other data values. | |
1383 | ||
aee2ab67 JA |
1384 | log_compression=int If this is set, fio will compress the IO logs as |
1385 | it goes, to keep the memory footprint lower. When a log | |
1386 | reaches the specified size, that chunk is removed and | |
1387 | compressed in the background. Given that IO logs are | |
1388 | fairly highly compressible, this yields a nice memory | |
1389 | savings for longer runs. The downside is that the | |
1390 | compression will consume some background CPU cycles, so | |
1391 | it may impact the run. This, however, is also true if | |
1392 | the logging ends up consuming most of the system memory. | |
1393 | So pick your poison. The IO logs are saved normally at the | |
1394 | end of a run, by decompressing the chunks and storing them | |
1395 | in the specified log file. This feature depends on the | |
1396 | availability of zlib. | |
1397 | ||
b26317c9 JA |
1398 | log_store_compressed=bool If set, and log_compression is also set, |
1399 | fio will store the log files in a compressed format. They | |
1400 | can be decompressed with fio, using the --inflate-log | |
1401 | command line parameter. The files will be stored with a | |
1402 | .fz suffix. | |
1403 | ||
f7fa2653 | 1404 | lockmem=int Pin down the specified amount of memory with mlock(2). Can |
71bfa161 JA |
1405 | potentially be used instead of removing memory or booting |
1406 | with less memory to simulate a smaller amount of memory. | |
81c6b6cd | 1407 | The amount specified is per worker. |
71bfa161 JA |
1408 | |
1409 | exec_prerun=str Before running this job, issue the command specified | |
74c8c488 JA |
1410 | through system(3). Output is redirected in a file called |
1411 | jobname.prerun.txt. | |
71bfa161 JA |
1412 | |
1413 | exec_postrun=str After the job completes, issue the command specified | |
74c8c488 JA |
1414 | though system(3). Output is redirected in a file called |
1415 | jobname.postrun.txt. | |
71bfa161 JA |
1416 | |
1417 | ioscheduler=str Attempt to switch the device hosting the file to the specified | |
1418 | io scheduler before running. | |
1419 | ||
0a839f30 JA |
1420 | disk_util=bool Generate disk utilization statistics, if the platform |
1421 | supports it. Defaults to on. | |
1422 | ||
02af0988 | 1423 | disable_lat=bool Disable measurements of total latency numbers. Useful |
9520ebb9 JA |
1424 | only for cutting back the number of calls to gettimeofday, |
1425 | as that does impact performance at really high IOPS rates. | |
1426 | Note that to really get rid of a large amount of these | |
1427 | calls, this option must be used with disable_slat and | |
1428 | disable_bw as well. | |
1429 | ||
02af0988 JA |
1430 | disable_clat=bool Disable measurements of completion latency numbers. See |
1431 | disable_lat. | |
1432 | ||
9520ebb9 | 1433 | disable_slat=bool Disable measurements of submission latency numbers. See |
02af0988 | 1434 | disable_slat. |
9520ebb9 JA |
1435 | |
1436 | disable_bw=bool Disable measurements of throughput/bandwidth numbers. See | |
02af0988 | 1437 | disable_lat. |
9520ebb9 | 1438 | |
83349190 YH |
1439 | clat_percentiles=bool Enable the reporting of percentiles of |
1440 | completion latencies. | |
1441 | ||
1442 | percentile_list=float_list Overwrite the default list of percentiles | |
1443 | for completion latencies. Each number is a floating | |
1444 | number in the range (0,100], and the maximum length of | |
1445 | the list is 20. Use ':' to separate the numbers, and | |
1446 | list the numbers in ascending order. For example, | |
1447 | --percentile_list=99.5:99.9 will cause fio to report | |
1448 | the values of completion latency below which 99.5% and | |
1449 | 99.9% of the observed latencies fell, respectively. | |
1450 | ||
23893646 JA |
1451 | clocksource=str Use the given clocksource as the base of timing. The |
1452 | supported options are: | |
1453 | ||
1454 | gettimeofday gettimeofday(2) | |
1455 | ||
1456 | clock_gettime clock_gettime(2) | |
1457 | ||
1458 | cpu Internal CPU clock source | |
1459 | ||
1460 | cpu is the preferred clocksource if it is reliable, as it | |
1461 | is very fast (and fio is heavy on time calls). Fio will | |
1462 | automatically use this clocksource if it's supported and | |
1463 | considered reliable on the system it is running on, unless | |
1464 | another clocksource is specifically set. For x86/x86-64 CPUs, | |
1465 | this means supporting TSC Invariant. | |
1466 | ||
993bf48b JA |
1467 | gtod_reduce=bool Enable all of the gettimeofday() reducing options |
1468 | (disable_clat, disable_slat, disable_bw) plus reduce | |
1469 | precision of the timeout somewhat to really shrink | |
1470 | the gettimeofday() call count. With this option enabled, | |
1471 | we only do about 0.4% of the gtod() calls we would have | |
1472 | done if all time keeping was enabled. | |
1473 | ||
be4ecfdf JA |
1474 | gtod_cpu=int Sometimes it's cheaper to dedicate a single thread of |
1475 | execution to just getting the current time. Fio (and | |
1476 | databases, for instance) are very intensive on gettimeofday() | |
1477 | calls. With this option, you can set one CPU aside for | |
1478 | doing nothing but logging current time to a shared memory | |
1479 | location. Then the other threads/processes that run IO | |
1480 | workloads need only copy that segment, instead of entering | |
1481 | the kernel with a gettimeofday() call. The CPU set aside | |
1482 | for doing these time calls will be excluded from other | |
1483 | uses. Fio will manually clear it from the CPU mask of other | |
1484 | jobs. | |
a696fa2a | 1485 | |
06842027 | 1486 | continue_on_error=str Normally fio will exit the job on the first observed |
f2bba182 RR |
1487 | failure. If this option is set, fio will continue the job when |
1488 | there is a 'non-fatal error' (EIO or EILSEQ) until the runtime | |
1489 | is exceeded or the I/O size specified is completed. If this | |
1490 | option is used, there are two more stats that are appended, | |
1491 | the total error count and the first error. The error field | |
1492 | given in the stats is the first error that was hit during the | |
1493 | run. | |
be4ecfdf | 1494 | |
06842027 SL |
1495 | The allowed values are: |
1496 | ||
1497 | none Exit on any IO or verify errors. | |
1498 | ||
1499 | read Continue on read errors, exit on all others. | |
1500 | ||
1501 | write Continue on write errors, exit on all others. | |
1502 | ||
1503 | io Continue on any IO error, exit on all others. | |
1504 | ||
1505 | verify Continue on verify errors, exit on all others. | |
1506 | ||
1507 | all Continue on all errors. | |
1508 | ||
1509 | 0 Backward-compatible alias for 'none'. | |
1510 | ||
1511 | 1 Backward-compatible alias for 'all'. | |
1512 | ||
8b28bd41 DM |
1513 | ignore_error=str Sometimes you want to ignore some errors during test |
1514 | in that case you can specify error list for each error type. | |
1515 | ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST | |
1516 | errors for given error type is separated with ':'. Error | |
1517 | may be symbol ('ENOSPC', 'ENOMEM') or integer. | |
1518 | Example: | |
1519 | ignore_error=EAGAIN,ENOSPC:122 | |
66c098b8 BC |
1520 | This option will ignore EAGAIN from READ, and ENOSPC and |
1521 | 122(EDQUOT) from WRITE. | |
8b28bd41 DM |
1522 | |
1523 | error_dump=bool If set dump every error even if it is non fatal, true | |
1524 | by default. If disabled only fatal error will be dumped | |
66c098b8 | 1525 | |
6adb38a1 JA |
1526 | cgroup=str Add job to this control group. If it doesn't exist, it will |
1527 | be created. The system must have a mounted cgroup blkio | |
1528 | mount point for this to work. If your system doesn't have it | |
1529 | mounted, you can do so with: | |
a696fa2a JA |
1530 | |
1531 | # mount -t cgroup -o blkio none /cgroup | |
1532 | ||
a696fa2a JA |
1533 | cgroup_weight=int Set the weight of the cgroup to this value. See |
1534 | the documentation that comes with the kernel, allowed values | |
1535 | are in the range of 100..1000. | |
71bfa161 | 1536 | |
7de87099 VG |
1537 | cgroup_nodelete=bool Normally fio will delete the cgroups it has created after |
1538 | the job completion. To override this behavior and to leave | |
1539 | cgroups around after the job completion, set cgroup_nodelete=1. | |
1540 | This can be useful if one wants to inspect various cgroup | |
1541 | files after job completion. Default: false | |
1542 | ||
e0b0d892 JA |
1543 | uid=int Instead of running as the invoking user, set the user ID to |
1544 | this value before the thread/process does any work. | |
1545 | ||
1546 | gid=int Set group ID, see uid. | |
1547 | ||
9e684a49 DE |
1548 | flow_id=int The ID of the flow. If not specified, it defaults to being a |
1549 | global flow. See flow. | |
1550 | ||
1551 | flow=int Weight in token-based flow control. If this value is used, then | |
1552 | there is a 'flow counter' which is used to regulate the | |
1553 | proportion of activity between two or more jobs. fio attempts | |
1554 | to keep this flow counter near zero. The 'flow' parameter | |
1555 | stands for how much should be added or subtracted to the flow | |
1556 | counter on each iteration of the main I/O loop. That is, if | |
1557 | one job has flow=8 and another job has flow=-1, then there | |
1558 | will be a roughly 1:8 ratio in how much one runs vs the other. | |
1559 | ||
1560 | flow_watermark=int The maximum value that the absolute value of the flow | |
1561 | counter is allowed to reach before the job must wait for a | |
1562 | lower value of the counter. | |
1563 | ||
1564 | flow_sleep=int The period of time, in microseconds, to wait after the flow | |
1565 | watermark has been exceeded before retrying operations | |
1566 | ||
de890a1e SL |
1567 | In addition, there are some parameters which are only valid when a specific |
1568 | ioengine is in use. These are used identically to normal parameters, with the | |
1569 | caveat that when used on the command line, they must come after the ioengine | |
1570 | that defines them is selected. | |
1571 | ||
1572 | [libaio] userspace_reap Normally, with the libaio engine in use, fio will use | |
1573 | the io_getevents system call to reap newly returned events. | |
1574 | With this flag turned on, the AIO ring will be read directly | |
1575 | from user-space to reap events. The reaping mode is only | |
1576 | enabled when polling for a minimum of 0 events (eg when | |
1577 | iodepth_batch_complete=0). | |
1578 | ||
0353050f JA |
1579 | [cpu] cpuload=int Attempt to use the specified percentage of CPU cycles. |
1580 | ||
1581 | [cpu] cpuchunks=int Split the load into cycles of the given time. In | |
1582 | microseconds. | |
1583 | ||
046395d7 JA |
1584 | [cpu] exit_on_io_done=bool Detect when IO threads are done, then exit. |
1585 | ||
de890a1e SL |
1586 | [netsplice] hostname=str |
1587 | [net] hostname=str The host name or IP address to use for TCP or UDP based IO. | |
1588 | If the job is a TCP listener or UDP reader, the hostname is not | |
b511c9aa SB |
1589 | used and must be omitted unless it is a valid UDP multicast |
1590 | address. | |
de890a1e SL |
1591 | |
1592 | [netsplice] port=int | |
1593 | [net] port=int The TCP or UDP port to bind to or connect to. | |
1594 | ||
b93b6a2e SB |
1595 | [netsplice] interface=str |
1596 | [net] interface=str The IP address of the network interface used to send or | |
1597 | receive UDP multicast | |
1598 | ||
d3a623de SB |
1599 | [netsplice] ttl=int |
1600 | [net] ttl=int Time-to-live value for outgoing UDP multicast packets. | |
1601 | Default: 1 | |
1602 | ||
1d360ffb JA |
1603 | [netsplice] nodelay=bool |
1604 | [net] nodelay=bool Set TCP_NODELAY on TCP connections. | |
1605 | ||
de890a1e SL |
1606 | [netsplice] protocol=str |
1607 | [netsplice] proto=str | |
1608 | [net] protocol=str | |
1609 | [net] proto=str The network protocol to use. Accepted values are: | |
1610 | ||
1611 | tcp Transmission control protocol | |
49ccb8c1 | 1612 | tcpv6 Transmission control protocol V6 |
f5cc3d0e | 1613 | udp User datagram protocol |
49ccb8c1 | 1614 | udpv6 User datagram protocol V6 |
de890a1e SL |
1615 | unix UNIX domain socket |
1616 | ||
1617 | When the protocol is TCP or UDP, the port must also be given, | |
1618 | as well as the hostname if the job is a TCP listener or UDP | |
1619 | reader. For unix sockets, the normal filename option should be | |
1620 | used and the port is invalid. | |
1621 | ||
1622 | [net] listen For TCP network connections, tell fio to listen for incoming | |
1623 | connections rather than initiating an outgoing connection. The | |
1624 | hostname must be omitted if this option is used. | |
b511c9aa | 1625 | [net] pingpong Normaly a network writer will just continue writing data, and |
7aeb1e94 JA |
1626 | a network reader will just consume packages. If pingpong=1 |
1627 | is set, a writer will send its normal payload to the reader, | |
1628 | then wait for the reader to send the same payload back. This | |
1629 | allows fio to measure network latencies. The submission | |
1630 | and completion latencies then measure local time spent | |
1631 | sending or receiving, and the completion latency measures | |
1632 | how long it took for the other end to receive and send back. | |
b511c9aa SB |
1633 | For UDP multicast traffic pingpong=1 should only be set for a |
1634 | single reader when multiple readers are listening to the same | |
1635 | address. | |
7aeb1e94 | 1636 | |
d54fce84 DM |
1637 | [e4defrag] donorname=str |
1638 | File will be used as a block donor(swap extents between files) | |
1639 | [e4defrag] inplace=int | |
66c098b8 | 1640 | Configure donor file blocks allocation strategy |
d54fce84 DM |
1641 | 0(default): Preallocate donor's file on init |
1642 | 1 : allocate space immidietly inside defragment event, | |
1643 | and free right after event | |
1644 | ||
de890a1e SL |
1645 | |
1646 | ||
71bfa161 JA |
1647 | 6.0 Interpreting the output |
1648 | --------------------------- | |
1649 | ||
1650 | fio spits out a lot of output. While running, fio will display the | |
1651 | status of the jobs created. An example of that would be: | |
1652 | ||
73c8b082 | 1653 | Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s] |
71bfa161 JA |
1654 | |
1655 | The characters inside the square brackets denote the current status of | |
1656 | each thread. The possible values (in typical life cycle order) are: | |
1657 | ||
1658 | Idle Run | |
1659 | ---- --- | |
1660 | P Thread setup, but not started. | |
1661 | C Thread created. | |
9c6f6316 | 1662 | I Thread initialized, waiting or generating necessary data. |
b0f65863 | 1663 | p Thread running pre-reading file(s). |
71bfa161 JA |
1664 | R Running, doing sequential reads. |
1665 | r Running, doing random reads. | |
1666 | W Running, doing sequential writes. | |
1667 | w Running, doing random writes. | |
1668 | M Running, doing mixed sequential reads/writes. | |
1669 | m Running, doing mixed random reads/writes. | |
1670 | F Running, currently waiting for fsync() | |
3d434057 | 1671 | f Running, finishing up (writing IO logs, etc) |
fc6bd43c | 1672 | V Running, doing verification of written data. |
71bfa161 | 1673 | E Thread exited, not reaped by main thread yet. |
4f7e57a4 JA |
1674 | _ Thread reaped, or |
1675 | X Thread reaped, exited with an error. | |
a5e371a6 | 1676 | K Thread reaped, exited due to signal. |
71bfa161 | 1677 | |
3e2e48a7 JA |
1678 | Fio will condense the thread string as not to take up more space on the |
1679 | command line as is needed. For instance, if you have 10 readers and 10 | |
1680 | writers running, the output would look like this: | |
1681 | ||
1682 | Jobs: 20 (f=20): [R(10),W(10)] [4.0% done] [2103MB/0KB/0KB /s] [538K/0/0 iops] [eta 57m:36s] | |
1683 | ||
1684 | Fio will still maintain the ordering, though. So the above means that jobs | |
1685 | 1..10 are readers, and 11..20 are writers. | |
1686 | ||
71bfa161 | 1687 | The other values are fairly self explanatory - number of threads |
c9f60304 JA |
1688 | currently running and doing io, rate of io since last check (read speed |
1689 | listed first, then write speed), and the estimated completion percentage | |
1690 | and time for the running group. It's impossible to estimate runtime of | |
4f7e57a4 JA |
1691 | the following groups (if any). Note that the string is displayed in order, |
1692 | so it's possible to tell which of the jobs are currently doing what. The | |
1693 | first character is the first job defined in the job file, and so forth. | |
71bfa161 JA |
1694 | |
1695 | When fio is done (or interrupted by ctrl-c), it will show the data for | |
1696 | each thread, group of threads, and disks in that order. For each data | |
1697 | direction, the output looks like: | |
1698 | ||
1699 | Client1 (g=0): err= 0: | |
35649e58 | 1700 | write: io= 32MB, bw= 666KB/s, iops=89 , runt= 50320msec |
6104ddb6 JA |
1701 | slat (msec): min= 0, max= 136, avg= 0.03, stdev= 1.92 |
1702 | clat (msec): min= 0, max= 631, avg=48.50, stdev=86.82 | |
b22989b9 | 1703 | bw (KB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68 |
e7823a94 | 1704 | cpu : usr=1.49%, sys=0.25%, ctx=7969, majf=0, minf=17 |
71619dc2 | 1705 | IO depths : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0% |
838bc709 JA |
1706 | submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% |
1707 | complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% | |
30061b97 | 1708 | issued r/w: total=0/32768, short=0/0 |
8abdce66 JA |
1709 | lat (msec): 2=1.6%, 4=0.0%, 10=3.2%, 20=12.8%, 50=38.4%, 100=24.8%, |
1710 | lat (msec): 250=15.2%, 500=0.0%, 750=0.0%, 1000=0.0%, >=2048=0.0% | |
71bfa161 JA |
1711 | |
1712 | The client number is printed, along with the group id and error of that | |
1713 | thread. Below is the io statistics, here for writes. In the order listed, | |
1714 | they denote: | |
1715 | ||
1716 | io= Number of megabytes io performed | |
1717 | bw= Average bandwidth rate | |
35649e58 | 1718 | iops= Average IOs performed per second |
71bfa161 | 1719 | runt= The runtime of that thread |
72fbda2a | 1720 | slat= Submission latency (avg being the average, stdev being the |
71bfa161 JA |
1721 | standard deviation). This is the time it took to submit |
1722 | the io. For sync io, the slat is really the completion | |
8a35c71e | 1723 | latency, since queue/complete is one operation there. This |
bf9a3edb | 1724 | value can be in milliseconds or microseconds, fio will choose |
8a35c71e | 1725 | the most appropriate base and print that. In the example |
0d237712 LAG |
1726 | above, milliseconds is the best scale. Note: in --minimal mode |
1727 | latencies are always expressed in microseconds. | |
71bfa161 JA |
1728 | clat= Completion latency. Same names as slat, this denotes the |
1729 | time from submission to completion of the io pieces. For | |
1730 | sync io, clat will usually be equal (or very close) to 0, | |
1731 | as the time from submit to complete is basically just | |
1732 | CPU time (io has already been done, see slat explanation). | |
1733 | bw= Bandwidth. Same names as the xlat stats, but also includes | |
1734 | an approximate percentage of total aggregate bandwidth | |
1735 | this thread received in this group. This last value is | |
1736 | only really useful if the threads in this group are on the | |
1737 | same disk, since they are then competing for disk access. | |
1738 | cpu= CPU usage. User and system time, along with the number | |
e7823a94 JA |
1739 | of context switches this thread went through, usage of |
1740 | system and user time, and finally the number of major | |
1741 | and minor page faults. | |
71619dc2 JA |
1742 | IO depths= The distribution of io depths over the job life time. The |
1743 | numbers are divided into powers of 2, so for example the | |
1744 | 16= entries includes depths up to that value but higher | |
1745 | than the previous entry. In other words, it covers the | |
1746 | range from 16 to 31. | |
838bc709 JA |
1747 | IO submit= How many pieces of IO were submitting in a single submit |
1748 | call. Each entry denotes that amount and below, until | |
1749 | the previous entry - eg, 8=100% mean that we submitted | |
1750 | anywhere in between 5-8 ios per submit call. | |
1751 | IO complete= Like the above submit number, but for completions instead. | |
30061b97 JA |
1752 | IO issued= The number of read/write requests issued, and how many |
1753 | of them were short. | |
ec118304 JA |
1754 | IO latencies= The distribution of IO completion latencies. This is the |
1755 | time from when IO leaves fio and when it gets completed. | |
1756 | The numbers follow the same pattern as the IO depths, | |
1757 | meaning that 2=1.6% means that 1.6% of the IO completed | |
8abdce66 JA |
1758 | within 2 msecs, 20=12.8% means that 12.8% of the IO |
1759 | took more than 10 msecs, but less than (or equal to) 20 msecs. | |
71bfa161 JA |
1760 | |
1761 | After each client has been listed, the group statistics are printed. They | |
1762 | will look like this: | |
1763 | ||
1764 | Run status group 0 (all jobs): | |
b22989b9 JA |
1765 | READ: io=64MB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec |
1766 | WRITE: io=64MB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec | |
71bfa161 JA |
1767 | |
1768 | For each data direction, it prints: | |
1769 | ||
1770 | io= Number of megabytes io performed. | |
1771 | aggrb= Aggregate bandwidth of threads in this group. | |
1772 | minb= The minimum average bandwidth a thread saw. | |
1773 | maxb= The maximum average bandwidth a thread saw. | |
1774 | mint= The smallest runtime of the threads in that group. | |
1775 | maxt= The longest runtime of the threads in that group. | |
1776 | ||
1777 | And finally, the disk statistics are printed. They will look like this: | |
1778 | ||
1779 | Disk stats (read/write): | |
1780 | sda: ios=16398/16511, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00% | |
1781 | ||
1782 | Each value is printed for both reads and writes, with reads first. The | |
1783 | numbers denote: | |
1784 | ||
1785 | ios= Number of ios performed by all groups. | |
1786 | merge= Number of merges io the io scheduler. | |
1787 | ticks= Number of ticks we kept the disk busy. | |
1788 | io_queue= Total time spent in the disk queue. | |
1789 | util= The disk utilization. A value of 100% means we kept the disk | |
1790 | busy constantly, 50% would be a disk idling half of the time. | |
1791 | ||
8423bd11 JA |
1792 | It is also possible to get fio to dump the current output while it is |
1793 | running, without terminating the job. To do that, send fio the USR1 signal. | |
06464907 JA |
1794 | You can also get regularly timed dumps by using the --status-interval |
1795 | parameter, or by creating a file in /tmp named fio-dump-status. If fio | |
1796 | sees this file, it will unlink it and dump the current output status. | |
8423bd11 | 1797 | |
71bfa161 JA |
1798 | |
1799 | 7.0 Terse output | |
1800 | ---------------- | |
1801 | ||
1802 | For scripted usage where you typically want to generate tables or graphs | |
6af019c9 | 1803 | of the results, fio can output the results in a semicolon separated format. |
71bfa161 JA |
1804 | The format is one long line of values, such as: |
1805 | ||
562c2d2f DN |
1806 | 2;card0;0;0;7139336;121836;60004;1;10109;27.932460;116.933948;220;126861;3495.446807;1085.368601;226;126864;3523.635629;1089.012448;24063;99944;50.275485%;59818.274627;5540.657370;7155060;122104;60004;1;8338;29.086342;117.839068;388;128077;5032.488518;1234.785715;391;128085;5061.839412;1236.909129;23436;100928;50.287926%;59964.832030;5644.844189;14.595833%;19.394167%;123706;0;7313;0.1%;0.1%;0.1%;0.1%;0.1%;0.1%;100.0%;0.00%;0.00%;0.00%;0.00%;0.00%;0.00%;0.01%;0.02%;0.05%;0.16%;6.04%;40.40%;52.68%;0.64%;0.01%;0.00%;0.01%;0.00%;0.00%;0.00%;0.00%;0.00% |
1807 | A description of this job goes here. | |
1808 | ||
1809 | The job description (if provided) follows on a second line. | |
71bfa161 | 1810 | |
525c2bfa JA |
1811 | To enable terse output, use the --minimal command line option. The first |
1812 | value is the version of the terse output format. If the output has to | |
1813 | be changed for some reason, this number will be incremented by 1 to | |
1814 | signify that change. | |
6820cb3b | 1815 | |
71bfa161 JA |
1816 | Split up, the format is as follows: |
1817 | ||
5e726d0a | 1818 | terse version, fio version, jobname, groupid, error |
71bfa161 | 1819 | READ status: |
312b4af2 | 1820 | Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec) |
de196b82 JA |
1821 | Submission latency: min, max, mean, deviation (usec) |
1822 | Completion latency: min, max, mean, deviation (usec) | |
1db92cb6 | 1823 | Completion latency percentiles: 20 fields (see below) |
de196b82 | 1824 | Total latency: min, max, mean, deviation (usec) |
0d237712 | 1825 | Bw (KB/s): min, max, aggregate percentage of total, mean, deviation |
71bfa161 | 1826 | WRITE status: |
312b4af2 | 1827 | Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec) |
de196b82 JA |
1828 | Submission latency: min, max, mean, deviation (usec) |
1829 | Completion latency: min, max, mean, deviation (usec) | |
1db92cb6 | 1830 | Completion latency percentiles: 20 fields (see below) |
de196b82 | 1831 | Total latency: min, max, mean, deviation (usec) |
0d237712 | 1832 | Bw (KB/s): min, max, aggregate percentage of total, mean, deviation |
046ee302 | 1833 | CPU usage: user, system, context switches, major faults, minor faults |
2270890c | 1834 | IO depths: <=1, 2, 4, 8, 16, 32, >=64 |
562c2d2f DN |
1835 | IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000 |
1836 | IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000 | |
f2f788dd JA |
1837 | Disk utilization: Disk name, Read ios, write ios, |
1838 | Read merges, write merges, | |
1839 | Read ticks, write ticks, | |
3d7cd9b4 | 1840 | Time spent in queue, disk utilization percentage |
de8f6de9 | 1841 | Additional Info (dependent on continue_on_error, default off): total # errors, first error code |
66c098b8 | 1842 | |
de8f6de9 | 1843 | Additional Info (dependent on description being set): Text description |
25c8b9d7 | 1844 | |
1db92cb6 JA |
1845 | Completion latency percentiles can be a grouping of up to 20 sets, so |
1846 | for the terse output fio writes all of them. Each field will look like this: | |
1847 | ||
1848 | 1.00%=6112 | |
1849 | ||
1850 | which is the Xth percentile, and the usec latency associated with it. | |
1851 | ||
f2f788dd JA |
1852 | For disk utilization, all disks used by fio are shown. So for each disk |
1853 | there will be a disk utilization section. | |
1854 | ||
25c8b9d7 PD |
1855 | |
1856 | 8.0 Trace file format | |
1857 | --------------------- | |
66c098b8 | 1858 | There are two trace file format that you can encounter. The older (v1) format |
25c8b9d7 PD |
1859 | is unsupported since version 1.20-rc3 (March 2008). It will still be described |
1860 | below in case that you get an old trace and want to understand it. | |
1861 | ||
1862 | In any case the trace is a simple text file with a single action per line. | |
1863 | ||
1864 | ||
1865 | 8.1 Trace file format v1 | |
1866 | ------------------------ | |
1867 | Each line represents a single io action in the following format: | |
1868 | ||
1869 | rw, offset, length | |
1870 | ||
1871 | where rw=0/1 for read/write, and the offset and length entries being in bytes. | |
1872 | ||
1873 | This format is not supported in Fio versions => 1.20-rc3. | |
1874 | ||
1875 | ||
1876 | 8.2 Trace file format v2 | |
1877 | ------------------------ | |
1878 | The second version of the trace file format was added in Fio version 1.17. | |
1879 | It allows to access more then one file per trace and has a bigger set of | |
1880 | possible file actions. | |
1881 | ||
1882 | The first line of the trace file has to be: | |
1883 | ||
1884 | fio version 2 iolog | |
1885 | ||
1886 | Following this can be lines in two different formats, which are described below. | |
1887 | ||
1888 | The file management format: | |
1889 | ||
1890 | filename action | |
1891 | ||
1892 | The filename is given as an absolute path. The action can be one of these: | |
1893 | ||
1894 | add Add the given filename to the trace | |
66c098b8 | 1895 | open Open the file with the given filename. The filename has to have |
25c8b9d7 PD |
1896 | been added with the add action before. |
1897 | close Close the file with the given filename. The file has to have been | |
1898 | opened before. | |
1899 | ||
1900 | ||
1901 | The file io action format: | |
1902 | ||
1903 | filename action offset length | |
1904 | ||
1905 | The filename is given as an absolute path, and has to have been added and opened | |
66c098b8 | 1906 | before it can be used with this format. The offset and length are given in |
25c8b9d7 PD |
1907 | bytes. The action can be one of these: |
1908 | ||
1909 | wait Wait for 'offset' microseconds. Everything below 100 is discarded. | |
1910 | read Read 'length' bytes beginning from 'offset' | |
1911 | write Write 'length' bytes beginning from 'offset' | |
1912 | sync fsync() the file | |
1913 | datasync fdatasync() the file | |
1914 | trim trim the given file from the given 'offset' for 'length' bytes | |
f2a2ce0e HL |
1915 | |
1916 | ||
1917 | 9.0 CPU idleness profiling | |
06464907 | 1918 | -------------------------- |
f2a2ce0e HL |
1919 | In some cases, we want to understand CPU overhead in a test. For example, |
1920 | we test patches for the specific goodness of whether they reduce CPU usage. | |
1921 | fio implements a balloon approach to create a thread per CPU that runs at | |
1922 | idle priority, meaning that it only runs when nobody else needs the cpu. | |
1923 | By measuring the amount of work completed by the thread, idleness of each | |
1924 | CPU can be derived accordingly. | |
1925 | ||
1926 | An unit work is defined as touching a full page of unsigned characters. Mean | |
1927 | and standard deviation of time to complete an unit work is reported in "unit | |
1928 | work" section. Options can be chosen to report detailed percpu idleness or | |
1929 | overall system idleness by aggregating percpu stats. |