1 .TH fio 1 "September 2007" "User Manual"
3 fio \- flexible I/O tester
6 [\fIoptions\fR] [\fIjobfile\fR]...
9 is a tool that will spawn a number of threads or processes doing a
10 particular type of I/O action as specified by the user.
11 The typical use of fio is to write a job file matching the I/O load
12 one wants to simulate.
15 .BI \-\-output \fR=\fPfilename
16 Write output to \fIfilename\fR.
18 .BI \-\-timeout \fR=\fPtimeout
19 Limit run time to \fItimeout\fR seconds.
22 Generate per-job latency logs.
25 Generate per-job bandwidth logs.
28 Print statistics in a terse, semicolon-delimited format.
30 .BI \-\-showcmd \fR=\fPjobfile
31 Convert \fIjobfile\fR to a set of command-line options.
34 Enable read-only safety checks.
36 .BI \-\-eta \fR=\fPwhen
37 Specifies when real-time ETA estimate should be printed. \fIwhen\fR may
38 be one of `always', `never' or `auto'.
40 .BI \-\-section \fR=\fPsec
41 Only run section \fIsec\fR from job file.
43 .BI \-\-cmdhelp \fR=\fPcommand
44 Print help information for \fIcommand\fR. May be `all' for all commands.
46 .BI \-\-debug \fR=\fPtype
47 Enable verbose tracing of various fio actions. May be `all' for all types
48 or individual types seperated by a comma (eg \-\-debug=io,file). `help' will
49 list all available tracing options.
52 Display usage information and exit.
55 Display version information and exit.
57 Job files are in `ini' format. They consist of one or more
58 job definitions, which begin with a job name in square brackets and
59 extend to the next job name. The job name can be any ASCII string
60 except `global', which has a special meaning. Following the job name is
61 a sequence of zero or more parameters, one per line, that define the
62 behavior of the job. Any line starting with a `;' or `#' character is
63 considered a comment and ignored.
65 If \fIjobfile\fR is specified as `-', the job file will be read from
68 The global section contains default parameters for jobs specified in the
69 job file. A job is only affected by global sections residing above it,
70 and there may be any number of global sections. Specific job definitions
71 may override any parameter set in global sections.
74 Some parameters may take arguments of a specific type. The types used are:
77 String: a sequence of alphanumeric characters.
80 SI integer: a whole number, possibly containing a suffix denoting the base unit
81 of the value. Accepted suffixes are `k', 'M', 'G', 'T', and 'P', denoting
82 kilo (1024), mega (1024^2), giga (1024^3), tera (1024^4), and peta (1024^5)
83 respectively. The suffix is not case sensitive. If prefixed with '0x', the
84 value is assumed to be base 16 (hexadecimal).
87 Boolean: a true or false value. `0' denotes false, `1' denotes true.
90 Integer range: a range of integers specified in the format
91 \fIlower\fR:\fIupper\fR or \fIlower\fR\-\fIupper\fR. \fIlower\fR and
92 \fIupper\fR may contain a suffix as described above. If an option allows two
93 sets of ranges, they are separated with a `,' or `/' character. For example:
98 May be used to override the job name. On the command line, this parameter
99 has the special purpose of signalling the start of a new job.
101 .BI description \fR=\fPstr
102 Human-readable description of the job. It is printed when the job is run, but
103 otherwise has no special purpose.
105 .BI directory \fR=\fPstr
106 Prefix filenames with this directory. Used to place files in a location other
109 .BI filename \fR=\fPstr
111 normally makes up a file name based on the job name, thread number, and file
112 number. If you want to share files between threads in a job or several jobs,
113 specify a \fIfilename\fR for each of them to override the default. If the I/O
114 engine used is `net', \fIfilename\fR is the host and port to connect to in the
115 format \fIhost\fR/\fIport\fR. If the I/O engine is file-based, you can specify
116 a number of files by separating the names with a `:' character. `\-' is a
117 reserved name, meaning stdin or stdout, depending on the read/write direction
120 .BI lockfile \fR=\fPstr
121 Fio defaults to not locking any files before it does IO to them. If a file or
122 file descriptor is shared, fio can serialize IO to that file to make the end
123 result consistent. This is usual for emulating real workloads that share files.
129 No locking. This is the default.
132 Only one thread or process may do IO at the time, excluding all others.
135 Read-write locking on the file. Many readers may access the file at the same
136 time, but writes get exclusive access.
139 The option may be post-fixed with a lock batch number. If set, then each
140 thread/process may do that amount of IOs to the file before giving up the lock.
141 Since lock acquisition is expensive, batching the lock/unlocks will speed up IO.
144 .BI opendir \fR=\fPstr
145 Recursively open any files below directory \fIstr\fR.
147 .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr
148 Type of I/O pattern. Accepted values are:
165 Mixed sequential reads and writes.
168 Mixed random reads and writes.
171 For mixed I/O, the default split is 50/50. For random I/O, the number of I/Os
172 to perform before getting a new offset can be specified by appending
173 `:\fIint\fR' to the pattern type. The default is 1.
176 .BI kb_base \fR=\fPint
177 The base unit for a kilobyte. The defacto base is 2^10, 1024. Storage
178 manufacturers like to use 10^3 or 1000 as a base ten unit instead, for obvious
179 reasons. Allow values are 1024 or 1000, with 1024 being the default.
181 .BI randrepeat \fR=\fPbool
182 Seed the random number generator in a predictable way so results are repeatable
183 across runs. Default: true.
185 .BI fadvise_hint \fR=\fPbool
186 Disable use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
187 are likely to be issued. Default: true.
190 Total size of I/O for this job. \fBfio\fR will run until this many bytes have
191 been transfered, unless limited by other options (\fBruntime\fR, for instance).
192 Unless \fBnr_files\fR and \fBfilesize\fR options are given, this amount will be
193 divided between the available files for the job.
195 .BI fill_device \fR=\fPbool
196 Sets size to something really large and waits for ENOSPC (no space left on
197 device) as the terminating condition. Only makes sense with sequential write.
198 For a read workload, the mount point will be filled first then IO started on
201 .BI filesize \fR=\fPirange
202 Individual file sizes. May be a range, in which case \fBfio\fR will select sizes
203 for files at random within the given range, limited to \fBsize\fR in total (if
204 that is given). If \fBfilesize\fR is not specified, each created file is the
207 .BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int]
208 Block size for I/O units. Default: 4k. Values for reads and writes can be
209 specified seperately in the format \fIread\fR,\fIwrite\fR, either of
210 which may be empty to leave that value at its default.
212 .BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange]
213 Specify a range of I/O block sizes. The issued I/O unit will always be a
214 multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies
215 to both reads and writes if only one range is given, but can be specified
216 seperately with a comma seperating the values. Example: bsrange=1k-4k,2k-8k.
217 Also (see \fBblocksize\fR).
219 .BI bssplit \fR=\fPstr
220 This option allows even finer grained control of the block sizes issued,
221 not just even splits between them. With this option, you can weight various
222 block sizes for exact control of the issued IO for a job that has mixed
223 block sizes. The format of the option is bssplit=blocksize/percentage,
224 optionally adding as many definitions as needed seperated by a colon.
225 Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
226 blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate
227 splits to reads and writes. The format is identical to what the
228 \fBbs\fR option accepts, the read and write parts are separated with a
231 .B blocksize_unaligned\fR,\fP bs_unaligned
232 If set, any size in \fBblocksize_range\fR may be used. This typically won't
233 work with direct I/O, as that normally requires sector alignment.
235 .BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int]
236 At what boundary to align random IO offsets. Defaults to the same as 'blocksize'
237 the minimum blocksize given. Minimum alignment is typically 512b
238 for using direct IO, though it usually depends on the hardware block size.
239 This option is mutually exclusive with using a random map for files, so it
240 will turn off that option.
243 Initialise buffers with all zeros. Default: fill buffers with random data.
246 If this option is given, fio will refill the IO buffers on every submit. The
247 default is to only fill it at init time and reuse that data. Only makes sense
248 if zero_buffers isn't specified, naturally. If data verification is enabled,
249 refill_buffers is also automatically enabled.
251 .BI nrfiles \fR=\fPint
252 Number of files to use for this job. Default: 1.
254 .BI openfiles \fR=\fPint
255 Number of files to keep open at the same time. Default: \fBnrfiles\fR.
257 .BI file_service_type \fR=\fPstr
258 Defines how files to service are selected. The following types are defined:
263 Choose a file at random
266 Round robin over open files (default).
268 Do each file in the set sequentially.
271 The number of I/Os to issue before switching a new file can be specified by
272 appending `:\fIint\fR' to the service type.
275 .BI ioengine \fR=\fPstr
276 Defines how the job issues I/O. The following types are defined:
281 Basic \fIread\fR\|(2) or \fIwrite\fR\|(2) I/O. \fIfseek\fR\|(2) is used to
282 position the I/O location.
285 Basic \fIpread\fR\|(2) or \fIpwrite\fR\|(2) I/O.
288 Basic \fIreadv\fR\|(2) or \fIwritev\fR\|(2) I/O. Will emulate queuing by
289 coalescing adjacents IOs into a single submission.
292 Linux native asynchronous I/O.
295 glibc POSIX asynchronous I/O using \fIaio_read\fR\|(3) and \fIaio_write\fR\|(3).
298 File is memory mapped with \fImmap\fR\|(2) and data copied using
302 \fIsplice\fR\|(2) is used to transfer the data and \fIvmsplice\fR\|(2) to
303 transfer data from user-space to the kernel.
306 Use the syslet system calls to make regular read/write asynchronous.
309 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
310 the target is an sg character device, we use \fIread\fR\|(2) and
311 \fIwrite\fR\|(2) for asynchronous I/O.
314 Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR
315 itself and for debugging and testing purposes.
318 Transfer over the network. \fBfilename\fR must be set appropriately to
319 `\fIhost\fR/\fIport\fR' regardless of data direction. If receiving, only the
320 \fIport\fR argument is used.
323 Like \fBnet\fR, but uses \fIsplice\fR\|(2) and \fIvmsplice\fR\|(2) to map data
327 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and
328 \fBcpucycles\fR parameters.
331 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface
332 approach to asycnronous I/O.
334 See <http://www.xmailserver.org/guasi\-lib.html>.
337 Loads an external I/O engine object file. Append the engine filename as
342 .BI iodepth \fR=\fPint
343 Number of I/O units to keep in flight against the file. Default: 1.
345 .BI iodepth_batch \fR=\fPint
346 Number of I/Os to submit at once. Default: \fBiodepth\fR.
348 .BI iodepth_batch_complete \fR=\fPint
349 This defines how many pieces of IO to retrieve at once. It defaults to 1 which
350 means that we'll ask for a minimum of 1 IO in the retrieval process from the
351 kernel. The IO retrieval will go on until we hit the limit set by
352 \fBiodepth_low\fR. If this variable is set to 0, then fio will always check for
353 completed events before queuing more IO. This helps reduce IO latency, at the
354 cost of more retrieval system calls.
356 .BI iodepth_low \fR=\fPint
357 Low watermark indicating when to start filling the queue again. Default:
360 .BI direct \fR=\fPbool
361 If true, use non-buffered I/O (usually O_DIRECT). Default: false.
363 .BI buffered \fR=\fPbool
364 If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
367 .BI offset \fR=\fPint
368 Offset in the file to start I/O. Data before the offset will not be touched.
371 How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
372 0, don't sync. Default: 0.
374 .BI fdatasync \fR=\fPint
375 Like \fBfsync\fR, but uses \fBfdatasync\fR\|(2) instead to only sync the
376 data parts of the file. Default: 0.
378 .BI overwrite \fR=\fPbool
379 If writing, setup the file first and do overwrites. Default: false.
381 .BI end_fsync \fR=\fPbool
382 Sync file contents when job exits. Default: false.
384 .BI fsync_on_close \fR=\fPbool
385 If true, sync file contents on close. This differs from \fBend_fsync\fR in that
386 it will happen on every close, not just at the end of the job. Default: false.
388 .BI rwmixcycle \fR=\fPint
389 How many milliseconds before switching between reads and writes for a mixed
390 workload. Default: 500ms.
392 .BI rwmixread \fR=\fPint
393 Percentage of a mixed workload that should be reads. Default: 50.
395 .BI rwmixwrite \fR=\fPint
396 Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and
397 \fBrwmixwrite\fR are given and do not sum to 100%, the latter of the two
398 overrides the first. This may interfere with a given rate setting, if fio is
399 asked to limit reads or writes to a certain rate. If that is the case, then
400 the distribution may be skewed. Default: 50.
403 Normally \fBfio\fR will cover every block of the file when doing random I/O. If
404 this parameter is given, a new offset will be chosen without looking at past
405 I/O history. This parameter is mutually exclusive with \fBverify\fR.
408 See \fBnorandommap\fR. If fio runs with the random block map enabled and it
409 fails to allocate the map, if this option is set it will continue without a
410 random block map. As coverage will not be as complete as with random maps, this
411 option is disabled by default.
414 Run job with given nice value. See \fInice\fR\|(2).
417 Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
420 .BI prioclass \fR=\fPint
421 Set I/O priority class. See \fIionice\fR\|(1).
423 .BI thinktime \fR=\fPint
424 Stall job for given number of microseconds between issuing I/Os.
426 .BI thinktime_spin \fR=\fPint
427 Pretend to spend CPU time for given number of microseconds, sleeping the rest
428 of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set.
430 .BI thinktime_blocks \fR=\fPint
431 Number of blocks to issue before waiting \fBthinktime\fR microseconds.
435 Cap bandwidth used by this job. The number is in bytes/sec, the normal postfix
436 rules apply. You can use \fBrate\fR=500k to limit reads and writes to 500k each,
437 or you can specify read and writes separately. Using \fBrate\fR=1m,500k would
438 limit reads to 1MB/sec and writes to 500KB/sec. Capping only reads or writes
439 can be done with \fBrate\fR=,500k or \fBrate\fR=500k,. The former will only
440 limit writes (to 500KB/sec), the latter will only limit reads.
442 .BI ratemin \fR=\fPint
443 Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth.
444 Failing to meet this requirement will cause the job to exit. The same format
445 as \fBrate\fR is used for read vs write separation.
447 .BI rate_iops \fR=\fPint
448 Cap the bandwidth to this number of IOPS. Basically the same as rate, just
449 specified independently of bandwidth. The same format as \fBrate\fR is used for
450 read vs write seperation. If \fBblocksize\fR is a range, the smallest block
451 size is used as the metric.
453 .BI rate_iops_min \fR=\fPint
454 If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR
455 is used for read vs write seperation.
457 .BI ratecycle \fR=\fPint
458 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
459 milliseconds. Default: 1000ms.
461 .BI cpumask \fR=\fPint
462 Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
463 may run on. See \fBsched_setaffinity\fR\|(2).
465 .BI cpus_allowed \fR=\fPstr
466 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
468 .BI startdelay \fR=\fPint
469 Delay start of job for the specified number of seconds.
471 .BI runtime \fR=\fPint
472 Terminate processing after the specified number of seconds.
475 If given, run for the specified \fBruntime\fR duration even if the files are
476 completely read or written. The same workload will be repeated as many times
477 as \fBruntime\fR allows.
479 .BI ramp_time \fR=\fPint
480 If set, fio will run the specified workload for this amount of time before
481 logging any performance numbers. Useful for letting performance settle before
482 logging results, thus minimizing the runtime required for stable results. Note
483 that the \fBramp_time\fR is considered lead in time for a job, thus it will
484 increase the total runtime if a special timeout or runtime is specified.
486 .BI invalidate \fR=\fPbool
487 Invalidate buffer-cache for the file prior to starting I/O. Default: true.
490 Use synchronous I/O for buffered writes. For the majority of I/O engines,
491 this means using O_SYNC. Default: false.
493 .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr
494 Allocation method for I/O unit buffer. Allowed values are:
499 Allocate memory with \fImalloc\fR\|(3).
502 Use shared memory buffers allocated through \fIshmget\fR\|(2).
505 Same as \fBshm\fR, but use huge pages as backing.
508 Use \fImmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
509 is given after the option in the format `:\fIfile\fR'.
512 Same as \fBmmap\fR, but use huge files as backing.
515 The amount of memory allocated is the maximum allowed \fBblocksize\fR for the
516 job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work,
517 the system must have free huge pages allocated. \fBmmaphuge\fR also needs to
518 have hugetlbfs mounted, and \fIfile\fR must point there. At least on Linux,
519 huge pages must be manually allocated. See \fB/proc/sys/vm/nr_hugehages\fR
520 and the documentation for that. Normally you just need to echo an appropriate
521 number, eg echoing 8 will ensure that the OS has 8 huge pages ready for
525 .BI iomem_align \fR=\fPint
526 This indiciates the memory alignment of the IO memory buffers. Note that the
527 given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR
528 the alignment of the following buffers are given by the \fBbs\fR used. In
529 other words, if using a \fBbs\fR that is a multiple of the page sized in the
530 system, all buffers will be aligned to this value. If using a \fBbs\fR that
531 is not page aligned, the alignment of subsequent IO memory buffers is the
532 sum of the \fBiomem_align\fR and \fBbs\fR used.
534 .BI hugepage\-size \fR=\fPint
535 Defines the size of a huge page. Must be at least equal to the system setting.
536 Should be a multiple of 1MB. Default: 4MB.
539 Terminate all jobs when one finishes. Default: wait for each job to finish.
541 .BI bwavgtime \fR=\fPint
542 Average bandwidth calculations over the given time in milliseconds. Default:
545 .BI create_serialize \fR=\fPbool
546 If true, serialize file creation for the jobs. Default: true.
548 .BI create_fsync \fR=\fPbool
549 \fIfsync\fR\|(2) data file after creation. Default: true.
551 .BI create_on_open \fR=\fPbool
552 If true, the files are not created until they are opened for IO by the job.
554 .BI pre_read \fR=\fPbool
555 If this is given, files will be pre-read into memory before starting the given
556 IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
557 pointless to pre-read and then drop the cache. This will only work for IO
558 engines that are seekable, since they allow you to read the same data
559 multiple times. Thus it will not work on eg network or splice IO.
561 .BI unlink \fR=\fPbool
562 Unlink job files when done. Default: false.
565 Specifies the number of iterations (runs of the same workload) of this job.
568 .BI do_verify \fR=\fPbool
569 Run the verify phase after a write phase. Only valid if \fBverify\fR is set.
572 .BI verify \fR=\fPstr
573 Method of verifying file contents after each iteration of the job. Allowed
578 .B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1
579 Store appropriate checksum in the header of each block.
582 Write extra information about each I/O (timestamp, block number, etc.). The
583 block number is verified.
586 Fill I/O buffers with a specific pattern that is used to verify. If the pattern
587 is < 4bytes, it can either be a decimal or a hexadecimal number. If the pattern
588 is > 4bytes, currently, it can only be a hexadecimal pattern starting with
592 Pretend to verify. Used for testing internals.
595 This option can be used for repeated burn-in tests of a system to make sure
596 that the written data is also correctly read back. If the data direction given
597 is a read or random read, fio will assume that it should verify a previously
598 written file. If the data direction includes any form of write, the verify will
599 be of the newly written data.
602 .BI verify_sort \fR=\fPbool
603 If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
604 read them back in a sorted manner. Default: true.
606 .BI verify_offset \fR=\fPint
607 Swap the verification header with data somewhere else in the block before
608 writing. It is swapped back before verifying.
610 .BI verify_interval \fR=\fPint
611 Write the verification header for this number of bytes, which should divide
612 \fBblocksize\fR. Default: \fBblocksize\fR.
614 .BI verify_fatal \fR=\fPbool
615 If true, exit the job on the first observed verification failure. Default:
618 .BI verify_async \fR=\fPint
619 Fio will normally verify IO inline from the submitting thread. This option
620 takes an integer describing how many async offload threads to create for IO
621 verification instead, causing fio to offload the duty of verifying IO contents
622 to one or more separate threads. If using this offload option, even sync IO
623 engines can benefit from using an \fBiodepth\fR setting higher than 1, as it
624 allows them to have IO in flight while verifies are running.
626 .BI verify_async_cpus \fR=\fPstr
627 Tell fio to set the given CPU affinity on the async IO verification threads.
628 See \fBcpus_allowed\fP for the format used.
631 Wait for preceeding jobs in the job file to exit before starting this one.
632 \fBstonewall\fR implies \fBnew_group\fR.
635 Start a new reporting group. If not given, all jobs in a file will be part
636 of the same reporting group, unless separated by a stonewall.
638 .BI numjobs \fR=\fPint
639 Number of clones (processes/threads performing the same workload) of this job.
643 If set, display per-group reports instead of per-job when \fBnumjobs\fR is
647 Use threads created with \fBpthread_create\fR\|(3) instead of processes created
648 with \fBfork\fR\|(2).
650 .BI zonesize \fR=\fPint
651 Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
653 .BI zoneskip \fR=\fPint
654 Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
657 .BI write_iolog \fR=\fPstr
658 Write the issued I/O patterns to the specified file.
660 .BI read_iolog \fR=\fPstr
661 Replay the I/O patterns contained in the specified file generated by
662 \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
664 .B write_bw_log \fR=\fPstr
665 If given, write a bandwidth log of the jobs in this job file. Can be used to
666 store data of the bandwidth of the jobs in their lifetime. The included
667 fio_generate_plots script uses gnuplot to turn these text files into nice
668 graphs. See \fBwrite_log_log\fR for behaviour of given filename. For this
669 option, the postfix is _bw.log.
672 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
673 filename is given with this option, the default filename of "jobname_type.log"
674 is used. Even if the filename is given, fio will still append the type of log.
676 .B disable_clat \fR=\fPbool
677 Disable measurements of completion latency numbers. Useful only for cutting
678 back the number of calls to gettimeofday, as that does impact performance at
679 really high IOPS rates. Note that to really get rid of a large amount of these
680 calls, this option must be used with disable_slat and disable_bw as well.
682 .B disable_slat \fR=\fPbool
683 Disable measurements of submission latency numbers. See \fBdisable_clat\fR.
685 .B disable_bw_measurement \fR=\fPbool
686 Disable measurements of throughput/bandwidth numbers. See \fBdisable_clat\fR.
688 .BI lockmem \fR=\fPint
689 Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
690 simulate a smaller amount of memory.
692 .BI exec_prerun \fR=\fPstr
693 Before running the job, execute the specified command with \fBsystem\fR\|(3).
695 .BI exec_postrun \fR=\fPstr
696 Same as \fBexec_prerun\fR, but the command is executed after the job completes.
698 .BI ioscheduler \fR=\fPstr
699 Attempt to switch the device hosting the file to the specified I/O scheduler.
701 .BI cpuload \fR=\fPint
702 If the job is a CPU cycle-eater, attempt to use the specified percentage of
705 .BI cpuchunks \fR=\fPint
706 If the job is a CPU cycle-eater, split the load into cycles of the
707 given time in milliseconds.
709 .BI disk_util \fR=\fPbool
710 Generate disk utilization statistics if the platform supports it. Default: true.
712 .BI gtod_reduce \fR=\fPbool
713 Enable all of the gettimeofday() reducing options (disable_clat, disable_slat,
714 disable_bw) plus reduce precision of the timeout somewhat to really shrink the
715 gettimeofday() call count. With this option enabled, we only do about 0.4% of
716 the gtod() calls we would have done if all time keeping was enabled.
718 .BI gtod_cpu \fR=\fPint
719 Sometimes it's cheaper to dedicate a single thread of execution to just getting
720 the current time. Fio (and databases, for instance) are very intensive on
721 gettimeofday() calls. With this option, you can set one CPU aside for doing
722 nothing but logging current time to a shared memory location. Then the other
723 threads/processes that run IO workloads need only copy that segment, instead of
724 entering the kernel with a gettimeofday() call. The CPU set aside for doing
725 these time calls will be excluded from other uses. Fio will manually clear it
726 from the CPU mask of other jobs.
728 .BI cgroup_root \fR=\fPstr
729 Root of the mounted blkio cgroup file systems. This is a Linux
730 specific IO controller. If your system doesn't have it mounted,
733 # mount -t cgroup -o blkio none /cgroup
735 The cgroup_root defaults to /cgroup, if mounted elsewhere please specify this
738 .BI cgroup \fR=\fPstr
739 Add job to this control group. If it doesn't exist, it will be created.
741 .BI cgroup_weight \fR=\fPint
742 Set the weight of the cgroup to this value. See the documentation that comes
743 with the kernel, allowed values are in the range of 100..1000.
745 While running, \fBfio\fR will display the status of the created jobs. For
749 Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
752 The characters in the first set of brackets denote the current status of each
753 threads. The possible values are:
759 Setup but not started.
765 Initialized, waiting.
768 Running, doing sequential reads.
771 Running, doing random reads.
774 Running, doing sequential writes.
777 Running, doing random writes.
780 Running, doing mixed sequential reads/writes.
783 Running, doing mixed random reads/writes.
786 Running, currently waiting for \fBfsync\fR\|(2).
789 Running, verifying written data.
792 Exited, not reaped by main thread.
795 Exited, thread reaped.
799 The second set of brackets shows the estimated completion percentage of
800 the current group. The third set shows the read and write I/O rate,
801 respectively. Finally, the estimated run time of the job is displayed.
803 When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data
804 for each thread, each group of threads, and each disk, in that order.
806 Per-thread statistics first show the threads client number, group-id, and
807 error code. The remaining figures are as follows:
811 Number of megabytes of I/O performed.
814 Average data rate (bandwidth).
820 Submission latency minimum, maximum, average and standard deviation. This is
821 the time it took to submit the I/O.
824 Completion latency minimum, maximum, average and standard deviation. This
825 is the time between submission and completion.
828 Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average
829 and standard deviation.
832 CPU usage statistics. Includes user and system time, number of context switches
833 this thread went through and number of major and minor page faults.
836 Distribution of I/O depths. Each depth includes everything less than (or equal)
837 to it, but greater than the previous depth.
840 Number of read/write requests issued, and number of short read/write requests.
843 Distribution of I/O completion latencies. The numbers follow the same pattern
847 The group statistics show:
852 Number of megabytes I/O performed.
855 Aggregate bandwidth of threads in the group.
858 Minimum average bandwidth a thread saw.
861 Maximum average bandwidth a thread saw.
864 Shortest runtime of threads in the group.
867 Longest runtime of threads in the group.
871 Finally, disk statistics are printed with reads first:
876 Number of I/Os performed by all groups.
879 Number of merges in the I/O scheduler.
882 Number of ticks we kept the disk busy.
885 Total time spent in the disk queue.
892 If the \fB\-\-minimal\fR option is given, the results will be printed in a
893 semicolon-delimited format suitable for scripted use. The fields are:
896 .B jobname, groupid, error
900 .B KB I/O, bandwidth \fR(KB/s)\fP, runtime \fR(ms)\fP
904 .B min, max, mean, standard deviation
908 .B min, max, mean, standard deviation
912 .B min, max, aggregate percentage of total, mean, standard deviation
918 .B KB I/O, bandwidth \fR(KB/s)\fP, runtime \fR(ms)\fP
922 .B min, max, mean, standard deviation
926 .B min, max, mean, standard deviation
930 .B min, max, aggregate percentage of total, mean, standard deviation
936 .B user, system, context switches, major page faults, minor page faults
939 IO depth distribution:
941 .B <=1, 2, 4, 8, 16, 32, >=64
944 IO latency distribution (ms):
946 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000
953 was written by Jens Axboe <jens.axboe@oracle.com>.
955 This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
956 on documentation by Jens Axboe.
958 Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
961 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
963 Sample jobfiles are available in the \fBexamples\fR directory.
projects / fio.git / blob