Remember to initialize return value in fixup_options()
[fio.git] / README
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1fio
2---
3
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4fio is a tool that will spawn a number of threads or processes doing a
5particular type of io action as specified by the user. fio takes a
6number of global parameters, each inherited by the thread unless
7otherwise parameters given to them overriding that setting is given.
8The typical use of fio is to write a job file matching the io load
9one wants to simulate.
ebac4655 10
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11
12Source
13------
14
15fio resides in a git repo, the canonical place is:
16
6b3eccb1 17git://git.kernel.dk/fio.git
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18
19The http protocol also works, path is the same.
2b02b546 20
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21Snapshots are frequently generated and they include the git meta data as
22well. You can download them here:
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23
24http://brick.kernel.dk/snaps/
25
1053a106 26
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27Binary packages
28---------------
29
30Debian:
31Starting with Debian "Squeeze", fio packages are part of the official
32Debian repository. http://packages.debian.org/search?keywords=fio
33
34Ubuntu:
35Starting with Ubuntu 10.04 LTS (aka "Lucid Lynx"), fio packages are part
36of the Ubuntu "universe" repository.
37http://packages.ubuntu.com/search?keywords=fio
38
39SUSE:
40Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository for SUSE
41variants, you can find them here:
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42http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio
43
d85b1add 44Red Hat, CentOS & Co:
a68594cb 45Dag Wieërs has RPMs for Red Hat related distros, find them here:
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46http://dag.wieers.com/rpm/packages/fio/
47
d85b1add 48Mandriva:
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49Mandriva has integrated fio into their package repository, so installing
50on that distro should be as easy as typing 'urpmi fio'.
51
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52Solaris:
53Packages for Solaris are available from OpenCSW. Install their pkgutil
54tool (http://www.opencsw.org/get-it/pkgutil/) and then install fio via
55'pkgutil -i fio'.
56
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57Windows:
58Bruce Cran <bruce@cran.org.uk> has fio packages for Windows at
59http://www.bluestop.org/fio .
60
2b02b546 61
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62Mailing list
63------------
64
65There's a mailing list associated with fio. It's meant for general
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66discussion, bug reporting, questions, and development - basically anything
67that has to do with fio. An automated mail detailing recent commits is
68automatically sent to the list at most daily. The list address is
69fio@vger.kernel.org, subscribe by sending an email to
70majordomo@vger.kernel.org with
71
72subscribe fio
73
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74in the body of the email. Archives can be found here:
75
76http://www.spinics.net/lists/fio/
77
78and archives for the old list can be found here:
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79
80http://maillist.kernel.dk/fio-devel/
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81
82
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83Building
84--------
85
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86Just type 'make' and 'make install'. If on BSD, for now you have to
87specify the BSD Makefile with -f and use gmake (not make), eg:
bbfd6b00 88
ecc314ba 89$ gmake -f Makefile.FreeBSD && gmake -f Makefile.FreeBSD install
bbfd6b00 90
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91Same goes for AIX:
92
93$ gmake -f Makefile.aix && gmake -f Makefile.aix install
94
edffcb96 95Likewise with OpenSolaris, use the Makefile.solaris to compile there.
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96The OpenSolaris make should work fine. This might change in the
97future if I opt for an autoconf type setup.
bbfd6b00 98
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99If your compile fails with an error like this:
100
101 CC gettime.o
102In file included from fio.h:23,
103 from gettime.c:8:
104os/os.h:15:20: error: libaio.h: No such file or directory
105In file included from gettime.c:8:
106fio.h:119: error: field 'iocb' has incomplete type
107make: *** [gettime.o] Error 1
108
109Check that you have the libaio development package installed. On RPM
110based distros, it's typically called libaio-devel.
111
bbfd6b00 112
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113Command line
114------------
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115
116$ fio
ee56ad50 117 --debug Enable some debugging options (see below)
b4692828 118 --output Write output to file
062c6022 119 --timeout Runtime in seconds
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120 --latency-log Generate per-job latency logs
121 --bandwidth-log Generate per-job bandwidth logs
122 --minimal Minimal (terse) output
123 --version Print version info and exit
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124 --help Print this page
125 --cmdhelp=cmd Print command help, "all" for all of them
cca73aa7 126 --showcmd Turn a job file into command line options
062c6022 127 --readonly Turn on safety read-only checks, preventing writes
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128 --eta=when When ETA estimate should be printed
129 May be "always", "never" or "auto"
01f06b63 130 --section=name Only run specified section in job file
2b386d25 131 --alloc-size=kb Set smalloc pool to this size in kb (def 1024)
a9523c6f 132 --warnings-fatal Fio parser warnings are fatal
e592a06b 133
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134
135Any parameters following the options will be assumed to be job files,
136unless they match a job file parameter. You can add as many as you want,
137each job file will be regarded as a separate group and fio will stonewall
138its execution.
972cfd25 139
ecc314ba 140The --readonly switch is an extra safety guard to prevent accidentally
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141turning on a write setting when that is not desired. Fio will only write
142if rw=write/randwrite/rw/randrw is given, but this extra safety net can
143be used as an extra precaution. It will also enable a write check in the
144io engine core to prevent an accidental write due to a fio bug.
145
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146The debug switch allows adding options that trigger certain logging
147options in fio. Currently the options are:
148
149 process Dump info related to processes
150 file Dump info related to file actions
151 io Dump info related to IO queuing
152 mem Dump info related to memory allocations
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153 blktrace Dump info related to blktrace setup
154 verify Dump info related to IO verification
155 all Enable all debug options
811a0d06 156 random Dump info related to random offset generation
a3d741fa 157 parse Dump info related to option matching and parsing
cd991b9e 158 diskutil Dump info related to disk utilization updates
5e1d306e 159 job:x Dump info only related to job number x
29adda3c 160 mutex Dump info only related to mutex up/down ops
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161 profile Dump info related to profile extensions
162 time Dump info related to internal time keeping
bd6f78b2 163 ? or help Show available debug options.
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164
165You can specify as many as you want, eg --debug=file,mem will enable
bd6f78b2 166file and memory debugging.
ee56ad50 167
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168The section switch is meant to make it easier to ship a bigger job file
169instead of several smaller ones. Say you define a job file with light,
170moderate, and heavy parts. Then you can ask fio to run the given part
171only by giving it a --section=heavy command line option. The section
172option only applies to job sections, the reserved 'global' section is
173always parsed and taken into account.
174
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175Fio has an internal allocator for shared memory called smalloc. It
176allocates shared structures from this pool. The pool defaults to 1024k
931823ca 177in size, and can grow to 128 pools. If running large jobs with randommap
2b386d25 178enabled it can run out of memory, in which case the --alloc-size switch
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179is handy for starting with a larger pool size. The backing store is
180files in /tmp. Fio cleans up after itself, while it is running you
181may see .fio_smalloc.* files in /tmp.
2b386d25 182
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183
184Job file
185--------
186
71bfa161 187See the HOWTO file for a more detailed description of parameters and what
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188they mean. This file contains the terse version. You can describe big and
189complex setups with the command line, but generally it's a lot easier to
71bfa161 190just write a simple job file to describe the workload. The job file format
4661f3d0 191is in the ini style format, as that is easy to read and write for the user.
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192
193The job file parameters are:
ebac4655 194
01452055 195 name=x Use 'x' as the identifier for this job.
61697c37 196 description=x 'x' is a text description of the job.
ebac4655 197 directory=x Use 'x' as the top level directory for storing files
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198 filename=x Force the use of 'x' as the filename for all files
199 in this thread. If not given, fio will make up
200 a suitable filename based on the thread and file
201 number.
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202 rw=x 'x' may be: read, randread, write, randwrite,
203 rw (read-write mix), randrw (read-write random mix)
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204 rwmixcycle=x Base cycle for switching between read and write
205 in msecs.
206 rwmixread=x 'x' percentage of rw mix ios will be reads. If
207 rwmixwrite is also given, the last of the two will
208 be used if they don't add up to 100%.
209 rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
210 rwmixread.
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211 rand_repeatable=x The sequence of random io blocks can be repeatable
212 across runs, if 'x' is 1.
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213 size=x Set file size to x bytes (x string can include k/m/g)
214 ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
78e7b3e7 215 posixaio for POSIX aio, solarisaio for Solaris
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216 native async IO, windowsaio for Windows native async IO,
217 sync for regular read/write io,
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218 psync for regular pread/pwrite io, vsync for regular
219 readv/writev (with queuing emulation) mmap for mmap'ed
220 io, syslet-rw for syslet driven read/write, splice for
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221 using splice/vmsplice, sg for direct SG_IO io, net
222 for network io, or cpuio for a cycler burner load. sg
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223 only works on Linux on SCSI (or SCSI-like devices, such
224 as usb-storage or sata/libata driven) devices. Fio also
225 has a null io engine, which is mainly used for testing
226 fio itself.
227
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228 iodepth=x For async io, allow 'x' ios in flight
229 overwrite=x If 'x', layout a write file first.
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230 nrfiles=x Spread io load over 'x' number of files per job,
231 if possible.
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232 prio=x Run io at prio X, 0-7 is the kernel allowed range
233 prioclass=x Run io at prio class X
234 bs=x Use 'x' for thread blocksize. May include k/m postfix.
235 bsrange=x-y Mix thread block sizes randomly between x and y. May
236 also include k/m postfix.
237 direct=x 1 for direct IO, 0 for buffered IO
238 thinktime=x "Think" x usec after each io
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239 rate=x Throttle rate to x KB/sec
240 ratemin=x Quit if rate of x KB/sec can't be met
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241 ratecycle=x ratemin averaged over x msecs
242 cpumask=x Only allow job to run on CPUs defined by mask.
d2e268b0 243 cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
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244 fsync=x If writing with buffered IO, fsync after every
245 'x' blocks have been written.
246 end_fsync=x If 'x', run fsync() after end-of-job.
ebac4655 247 startdelay=x Start this thread x seconds after startup
03b74b3e 248 runtime=x Terminate x seconds after startup. Can include a
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249 normal time suffix if not given in seconds, such as
250 'm' for minutes, 'h' for hours, and 'd' for days.
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251 offset=x Start io at offset x (x string can include k/m/g)
252 invalidate=x Invalidate page cache for file prior to doing io
795407ca 253 sync=x Use sync writes if x and writing buffered IO.
ebac4655 254 mem=x If x == malloc, use malloc for buffers. If x == shm,
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255 use shared memory for buffers. If x == mmap, use
256 anonymous mmap.
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257 exitall When one thread quits, terminate the others
258 bwavgtime=x Average bandwidth stats over an x msec window.
259 create_serialize=x If 'x', serialize file creation.
260 create_fsync=x If 'x', run fsync() after file creation.
f6cbb269 261 unlink If set, unlink files when done.
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262 loops=x Run the job 'x' number of times.
263 verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
264 use crc32 for verifies. md5 is 'safer', but crc32 is
265 a lot faster. Only makes sense for writing to a file.
bac39e0e 266 For other types of checksumming, see HOWTO.
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267 stonewall Wait for preceeding jobs to end before running.
268 numjobs=x Create 'x' similar entries for this job
269 thread Use pthreads instead of forked jobs
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270 zonesize=x
271 zoneskip=y Zone options must be paired. If given, the job
272 will skip y bytes for every x read/written. This
273 can be used to gauge hard drive speed over the entire
274 platter, without reading everything. Both x/y can
275 include k/m/g suffix.
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276 iolog=x Open and read io pattern from file 'x'. The file must
277 contain one io action per line in the following format:
278 rw, offset, length
279 where with rw=0/1 for read/write, and the offset
280 and length entries being in bytes.
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281 write_iolog=x Write an iolog to file 'x' in the same format as iolog.
282 The iolog options are exclusive, if both given the
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283 read iolog will be performed. Specify a separate file
284 for each job, otherwise the iologs will be interspersed
285 and the file may be corrupt.
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286 write_bw_log Write a bandwidth log.
287 write_lat_log Write a latency log.
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288 lockmem=x Lock down x amount of memory on the machine, to
289 simulate a machine with less memory available. x can
290 include k/m/g suffix.
b6f4d880 291 nice=x Run job at given nice value.
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292 exec_prerun=x Run 'x' before job io is begun.
293 exec_postrun=x Run 'x' after job io has finished.
da86774e 294 ioscheduler=x Use ioscheduler 'x' for this job.
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295 cpuload=x For a CPU io thread, percentage of CPU time to attempt
296 to burn.
ba0fbe10 297 cpuchunks=x Split burn cycles into pieces of x usecs.
ebac4655 298
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300
301Platforms
302---------
303
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304Fio works on (at least) Linux, Solaris, AIX, OSX, NetBSD, Windows and FreeBSD.
305Some features and/or options may only be available on some of the platforms,
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306typically because those features only apply to that platform (like the
307solarisaio engine, or the splice engine on Linux).
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308
309Some features are not available on FreeBSD/Solaris even if they could be
310implemented, I'd be happy to take patches for that. An example of that is
311disk utility statistics and (I think) huge page support, support for that
312does exist in FreeBSD/Solaris.
313
314Fio uses pthread mutexes for signalling and locking and FreeBSD does not
315support process shared pthread mutexes. As a result, only threads are
316supported on FreeBSD. This could be fixed with sysv ipc locking or
317other locking alternatives.
318
319Other *BSD platforms are untested, but fio should work there almost out
320of the box. Since I don't do test runs or even compiles on those platforms,
321your mileage may vary. Sending me patches for other platforms is greatly
322appreciated. There's a lot of value in having the same test/benchmark tool
323available on all platforms.
324
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325Note that POSIX aio is not enabled by default on AIX. If you get messages like:
326
327 Symbol resolution failed for /usr/lib/libc.a(posix_aio.o) because:
328 Symbol _posix_kaio_rdwr (number 2) is not exported from dependent module /unix.
329
330you need to enable POSIX aio. Run the following commands as root:
331
332 # lsdev -C -l posix_aio0
333 posix_aio0 Defined Posix Asynchronous I/O
334 # cfgmgr -l posix_aio0
335 # lsdev -C -l posix_aio0
336 posix_aio0 Available Posix Asynchronous I/O
337
338POSIX aio should work now. To make the change permanent:
339
340 # chdev -l posix_aio0 -P -a autoconfig='available'
341 posix_aio0 changed
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342
343
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344Author
345------
346
aae22ca7 347Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
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348of the Linux IO subsystem and schedulers. He got tired of writing
349specific test applications to simulate a given workload, and found that
350the existing io benchmark/test tools out there weren't flexible enough
351to do what he wanted.
352
aae22ca7 353Jens Axboe <axboe@kernel.dk> 20060905
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