4 fio is a tool that will spawn a number of threads or processes doing a
5 particular type of io action as specified by the user. fio takes a
6 number of global parameters, each inherited by the thread unless
7 otherwise parameters given to them overriding that setting is given.
8 The typical use of fio is to write a job file matching the io load
15 fio resides in a git repo, the canonical place is:
17 git://git.kernel.dk/fio.git
19 The http protocol also works, path is the same.
21 Snapshots are frequently generated and they include the git meta data as
22 well. You can download them here:
24 http://brick.kernel.dk/snaps/
26 Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository for
27 SUSE variants, you can find them here:
29 http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio
31 Dag Wieƫrs has RPMs for Red Hat related distros, find them here:
33 http://dag.wieers.com/rpm/packages/fio/
35 Mandriva has integrated fio into their package repository, so installing
36 on that distro should be as easy as typing 'urpmi fio'.
42 There's a mailing list associated with fio. It's meant for general
43 discussion, bug reporting, questions, and development - basically anything
44 that has to do with fio. An automated mail detailing recent commits is
45 automatically sent to the list at most daily. The list address is
46 fio@vger.kernel.org, subscribe by sending an email to
47 majordomo@vger.kernel.org with
51 in the body of the email. There is no archive for the new list yet,
52 archives for the old list can be found here:
54 http://maillist.kernel.dk/fio-devel/
60 Just type 'make' and 'make install'. If on FreeBSD, for now you have to
61 specify the FreeBSD Makefile with -f and use gmake (not make), eg:
63 $ gmake -f Makefile.Freebsd && gmake -f Makefile.FreeBSD install
65 Likewise with OpenSolaris, use the Makefile.solaris to compile there.
66 The OpenSolaris make should work fine. This might change in the
67 future if I opt for an autoconf type setup.
69 If your compile fails with an error like this:
72 In file included from fio.h:23,
74 os/os.h:15:20: error: libaio.h: No such file or directory
75 In file included from gettime.c:8:
76 fio.h:119: error: field 'iocb' has incomplete type
77 make: *** [gettime.o] Error 1
79 Check that you have the libaio development package installed. On RPM
80 based distros, it's typically called libaio-devel.
87 --debug Enable some debugging options (see below)
88 --output Write output to file
89 --timeout Runtime in seconds
90 --latency-log Generate per-job latency logs
91 --bandwidth-log Generate per-job bandwidth logs
92 --minimal Minimal (terse) output
93 --version Print version info and exit
94 --help Print this page
95 --cmdhelp=cmd Print command help, "all" for all of them
96 --showcmd Turn a job file into command line options
97 --readonly Turn on safety read-only checks, preventing writes
98 --eta=when When ETA estimate should be printed
99 May be "always", "never" or "auto"
100 --section=name Only run specified section in job file
101 --alloc-size=kb Set smalloc pool to this size in kb (def 1024)
104 Any parameters following the options will be assumed to be job files,
105 unless they match a job file parameter. You can add as many as you want,
106 each job file will be regarded as a separate group and fio will stonewall
109 The --readonly switch is an extra safety guard to prevent accidentically
110 turning on a write setting when that is not desired. Fio will only write
111 if rw=write/randwrite/rw/randrw is given, but this extra safety net can
112 be used as an extra precaution. It will also enable a write check in the
113 io engine core to prevent an accidental write due to a fio bug.
115 The debug switch allows adding options that trigger certain logging
116 options in fio. Currently the options are:
118 process Dump info related to processes
119 file Dump info related to file actions
120 io Dump info related to IO queuing
121 mem Dump info related to memory allocations
122 blktrace Dump info related to blktrace setup
123 verify Dump info related to IO verification
124 all Enable all debug options
125 random Dump info related to random offset generation
126 parse Dump info related to option matching and parsing
127 diskutil Dump info related to disk utilization updates
128 job:x Dump info only related to job number x
129 ? or help Show available debug options.
131 You can specify as many as you want, eg --debug=file,mem will enable
132 file and memory debugging.
134 The section switch is meant to make it easier to ship a bigger job file
135 instead of several smaller ones. Say you define a job file with light,
136 moderate, and heavy parts. Then you can ask fio to run the given part
137 only by giving it a --section=heavy command line option. The section
138 option only applies to job sections, the reserved 'global' section is
139 always parsed and taken into account.
141 Fio has an internal allocator for shared memory called smalloc. It
142 allocates shared structures from this pool. The pool defaults to 1024k
143 in size, and can grow to 32 pools. If running large jobs with randommap
144 enabled it can run out of memory, in which case the --alloc-size switch
145 is handy for starting with a larger pool size.
151 See the HOWTO file for a more detailed description of parameters and what
152 they mean. This file contains the terse version. You can describe big and
153 complex setups with the command line, but generally it's a lot easier to
154 just write a simple job file to describe the workload. The job file format
155 is in the ini style format, as that is easy to read and write for the user.
157 The job file parameters are:
159 name=x Use 'x' as the identifier for this job.
160 description=x 'x' is a text description of the job.
161 directory=x Use 'x' as the top level directory for storing files
162 filename=x Force the use of 'x' as the filename for all files
163 in this thread. If not given, fio will make up
164 a suitable filename based on the thread and file
166 rw=x 'x' may be: read, randread, write, randwrite,
167 rw (read-write mix), randrw (read-write random mix)
168 rwmixcycle=x Base cycle for switching between read and write
170 rwmixread=x 'x' percentage of rw mix ios will be reads. If
171 rwmixwrite is also given, the last of the two will
172 be used if they don't add up to 100%.
173 rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
175 rand_repeatable=x The sequence of random io blocks can be repeatable
176 across runs, if 'x' is 1.
177 size=x Set file size to x bytes (x string can include k/m/g)
178 ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
179 posixaio for POSIX aio, solarisaio for Solaris
180 native async IO, sync for regular read/write io,
181 psync for regular pread/pwrite io, vsync for regular
182 readv/writev (with queuing emulation) mmap for mmap'ed
183 io, syslet-rw for syslet driven read/write, splice for
184 using splice/vmsplice, sg for direct SG_IO io, net
185 for network io, or cpuio for a cycler burner load. sg
186 only works on Linux on SCSI (or SCSI-like devices, such
187 as usb-storage or sata/libata driven) devices. Fio also
188 has a null io engine, which is mainly used for testing
191 iodepth=x For async io, allow 'x' ios in flight
192 overwrite=x If 'x', layout a write file first.
193 nrfiles=x Spread io load over 'x' number of files per job,
195 prio=x Run io at prio X, 0-7 is the kernel allowed range
196 prioclass=x Run io at prio class X
197 bs=x Use 'x' for thread blocksize. May include k/m postfix.
198 bsrange=x-y Mix thread block sizes randomly between x and y. May
199 also include k/m postfix.
200 direct=x 1 for direct IO, 0 for buffered IO
201 thinktime=x "Think" x usec after each io
202 rate=x Throttle rate to x KiB/sec
203 ratemin=x Quit if rate of x KiB/sec can't be met
204 ratecycle=x ratemin averaged over x msecs
205 cpumask=x Only allow job to run on CPUs defined by mask.
206 cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
207 fsync=x If writing with buffered IO, fsync after every
208 'x' blocks have been written.
209 end_fsync=x If 'x', run fsync() after end-of-job.
210 startdelay=x Start this thread x seconds after startup
211 runtime=x Terminate x seconds after startup. Can include a
212 normal time suffix if not given in seconds, such as
213 'm' for minutes, 'h' for hours, and 'd' for days.
214 offset=x Start io at offset x (x string can include k/m/g)
215 invalidate=x Invalidate page cache for file prior to doing io
216 sync=x Use sync writes if x and writing buffered IO.
217 mem=x If x == malloc, use malloc for buffers. If x == shm,
218 use shared memory for buffers. If x == mmap, use
220 exitall When one thread quits, terminate the others
221 bwavgtime=x Average bandwidth stats over an x msec window.
222 create_serialize=x If 'x', serialize file creation.
223 create_fsync=x If 'x', run fsync() after file creation.
224 unlink If set, unlink files when done.
225 loops=x Run the job 'x' number of times.
226 verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
227 use crc32 for verifies. md5 is 'safer', but crc32 is
228 a lot faster. Only makes sense for writing to a file.
229 For other types of checksumming, see HOWTO.
230 stonewall Wait for preceeding jobs to end before running.
231 numjobs=x Create 'x' similar entries for this job
232 thread Use pthreads instead of forked jobs
234 zoneskip=y Zone options must be paired. If given, the job
235 will skip y bytes for every x read/written. This
236 can be used to gauge hard drive speed over the entire
237 platter, without reading everything. Both x/y can
238 include k/m/g suffix.
239 iolog=x Open and read io pattern from file 'x'. The file must
240 contain one io action per line in the following format:
242 where with rw=0/1 for read/write, and the offset
243 and length entries being in bytes.
244 write_iolog=x Write an iolog to file 'x' in the same format as iolog.
245 The iolog options are exclusive, if both given the
246 read iolog will be performed.
247 write_bw_log Write a bandwidth log.
248 write_lat_log Write a latency log.
249 lockmem=x Lock down x amount of memory on the machine, to
250 simulate a machine with less memory available. x can
251 include k/m/g suffix.
252 nice=x Run job at given nice value.
253 exec_prerun=x Run 'x' before job io is begun.
254 exec_postrun=x Run 'x' after job io has finished.
255 ioscheduler=x Use ioscheduler 'x' for this job.
256 cpuload=x For a CPU io thread, percentage of CPU time to attempt
258 cpuchunks=x Split burn cycles into pieces of x usecs.
264 Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
265 of the Linux IO subsystem and schedulers. He got tired of writing
266 specific test applications to simulate a given workload, and found that
267 the existing io benchmark/test tools out there weren't flexible enough
268 to do what he wanted.
270 Jens Axboe <axboe@kernel.dk> 20060905