netsplice: fix a few typos
[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.
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11
12Source
13------
14
15fio resides in a git repo, the canonical place is:
16
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17git://git.kernel.dk/data/git/fio.git
18
19The http protocol also works, path is the same.
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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
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26Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository for
27SUSE variants, you can find them here:
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28
29http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio
30
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31Dag Wieƫrs has RPMs for Red Hat related distros, find them here:
32
33http://dag.wieers.com/rpm/packages/fio/
34
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36Mailing list
37------------
38
39There's a mailing list associated with fio. It's meant for general
40discussion, bug reporting, questions - basically anything that has to
41do with fio. An automated mail detailing recent commits is automatically
42sent to the list at most daily. The list address is fio-devel@kernel.dk,
43subscribe by sending an empty email to fio-devel+subscribe@kernel.dk.
44
45
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46Building
47--------
48
49Just type 'make' and 'make install'. If on FreeBSD, for now you have to
50specify the FreeBSD Makefile with -f, eg:
51
52$ make -f Makefile.Freebsd && make -f Makefile.FreeBSD install
53
edffcb96 54Likewise with OpenSolaris, use the Makefile.solaris to compile there.
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55This might change in the future if I opt for an autoconf type setup.
56
57
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58Command line
59------------
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60
61$ fio
b4692828 62 --output Write output to file
03b74b3e 63 --runtime Runtime in seconds
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64 --latency-log Generate per-job latency logs
65 --bandwidth-log Generate per-job bandwidth logs
66 --minimal Minimal (terse) output
67 --version Print version info and exit
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68 --help Print this page
69 --cmdhelp=cmd Print command help, "all" for all of them
cca73aa7 70 --showcmd Turn a job file into command line options
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71
72Any parameters following the options will be assumed to be job files,
73unless they match a job file parameter. You can add as many as you want,
74each job file will be regarded as a separate group and fio will stonewall
75its execution.
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77
78Job file
79--------
80
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81See the HOWTO file for a more detailed description of parameters and what
82they mean. This file contains the terse version. Only a few options can
83be controlled with command line parameters, generally it's a lot easier to
84just write a simple job file to describe the workload. The job file format
85is in the ini style format, as it's easy to read and write for the user.
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86
87The job file parameters are:
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01452055 89 name=x Use 'x' as the identifier for this job.
61697c37 90 description=x 'x' is a text description of the job.
ebac4655 91 directory=x Use 'x' as the top level directory for storing files
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92 filename=x Force the use of 'x' as the filename for all files
93 in this thread. If not given, fio will make up
94 a suitable filename based on the thread and file
95 number.
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96 rw=x 'x' may be: read, randread, write, randwrite,
97 rw (read-write mix), randrw (read-write random mix)
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98 rwmixcycle=x Base cycle for switching between read and write
99 in msecs.
100 rwmixread=x 'x' percentage of rw mix ios will be reads. If
101 rwmixwrite is also given, the last of the two will
102 be used if they don't add up to 100%.
103 rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
104 rwmixread.
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105 rand_repeatable=x The sequence of random io blocks can be repeatable
106 across runs, if 'x' is 1.
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107 size=x Set file size to x bytes (x string can include k/m/g)
108 ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
109 posixaio for POSIX aio, sync for regular read/write io,
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110 mmap for mmap'ed io, syslet-rw for syslet driven
111 read/write, splice for using splice/vmsplice,
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112 sgio for direct SG_IO io, net for network io, or cpuio
113 for a cycler burner load. sgio only works on Linux on
114 SCSI (or SCSI-like devices, such as usb-storage or
115 sata/libata driven) devices. Fio also has a null io
116 engine, which is mainly used for testing fio itself.
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117 iodepth=x For async io, allow 'x' ios in flight
118 overwrite=x If 'x', layout a write file first.
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119 nrfiles=x Spread io load over 'x' number of files per job,
120 if possible.
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121 prio=x Run io at prio X, 0-7 is the kernel allowed range
122 prioclass=x Run io at prio class X
123 bs=x Use 'x' for thread blocksize. May include k/m postfix.
124 bsrange=x-y Mix thread block sizes randomly between x and y. May
125 also include k/m postfix.
126 direct=x 1 for direct IO, 0 for buffered IO
127 thinktime=x "Think" x usec after each io
128 rate=x Throttle rate to x KiB/sec
129 ratemin=x Quit if rate of x KiB/sec can't be met
130 ratecycle=x ratemin averaged over x msecs
131 cpumask=x Only allow job to run on CPUs defined by mask.
d2e268b0 132 cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
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133 fsync=x If writing with buffered IO, fsync after every
134 'x' blocks have been written.
135 end_fsync=x If 'x', run fsync() after end-of-job.
ebac4655 136 startdelay=x Start this thread x seconds after startup
03b74b3e 137 runtime=x Terminate x seconds after startup. Can include a
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138 normal time suffix if not given in seconds, such as
139 'm' for minutes, 'h' for hours, and 'd' for days.
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140 offset=x Start io at offset x (x string can include k/m/g)
141 invalidate=x Invalidate page cache for file prior to doing io
795407ca 142 sync=x Use sync writes if x and writing buffered IO.
ebac4655 143 mem=x If x == malloc, use malloc for buffers. If x == shm,
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144 use shared memory for buffers. If x == mmap, use
145 anonymous mmap.
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146 exitall When one thread quits, terminate the others
147 bwavgtime=x Average bandwidth stats over an x msec window.
148 create_serialize=x If 'x', serialize file creation.
149 create_fsync=x If 'x', run fsync() after file creation.
f6cbb269 150 unlink If set, unlink files when done.
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151 loops=x Run the job 'x' number of times.
152 verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
153 use crc32 for verifies. md5 is 'safer', but crc32 is
154 a lot faster. Only makes sense for writing to a file.
155 stonewall Wait for preceeding jobs to end before running.
156 numjobs=x Create 'x' similar entries for this job
157 thread Use pthreads instead of forked jobs
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158 zonesize=x
159 zoneskip=y Zone options must be paired. If given, the job
160 will skip y bytes for every x read/written. This
161 can be used to gauge hard drive speed over the entire
162 platter, without reading everything. Both x/y can
163 include k/m/g suffix.
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164 iolog=x Open and read io pattern from file 'x'. The file must
165 contain one io action per line in the following format:
166 rw, offset, length
167 where with rw=0/1 for read/write, and the offset
168 and length entries being in bytes.
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169 write_iolog=x Write an iolog to file 'x' in the same format as iolog.
170 The iolog options are exclusive, if both given the
171 read iolog will be performed.
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172 write_bw_log Write a bandwidth log.
173 write_lat_log Write a latency log.
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174 lockmem=x Lock down x amount of memory on the machine, to
175 simulate a machine with less memory available. x can
176 include k/m/g suffix.
b6f4d880 177 nice=x Run job at given nice value.
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178 exec_prerun=x Run 'x' before job io is begun.
179 exec_postrun=x Run 'x' after job io has finished.
da86774e 180 ioscheduler=x Use ioscheduler 'x' for this job.
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181 cpuload=x For a CPU io thread, percentage of CPU time to attempt
182 to burn.
ba0fbe10 183 cpuchunks=x Split burn cycles into pieces of x usecs.
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186Author
187------
188
aae22ca7 189Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
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190of the Linux IO subsystem and schedulers. He got tired of writing
191specific test applications to simulate a given workload, and found that
192the existing io benchmark/test tools out there weren't flexible enough
193to do what he wanted.
194
aae22ca7 195Jens Axboe <axboe@kernel.dk> 20060905
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