section residing above it. If the first character in a line is a ';' or a
'#', the entire line is discarded as a comment.
-So lets look at a really simple job file that define to threads, each
+So let's look at a really simple job file that defines two processes, each
randomly reading from a 128MiB file.
; -- start job file --
$ fio --name=global --rw=randread --size=128m --name=job1 --name=job2
-Lets look at an example that have a number of processes writing randomly
+Let's look at an example that has a number of processes writing randomly
to files.
; -- start job file --
$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
+fio also supports environment variable expansion in job files. Any
+substring of the form "${VARNAME}" as part of an option value (in other
+words, on the right of the `='), will be expanded to the value of the
+environment variable called VARNAME. If no such environment variable
+is defined, or VARNAME is the empty string, the empty string will be
+substituted.
+
+As an example, let's look at a sample fio invocation and job file:
+
+$ SIZE=64m NUMJOBS=4 fio jobfile.fio
+
+; -- start job file --
+[random-writers]
+rw=randwrite
+size=${SIZE}
+numjobs=${NUMJOBS}
+; -- end job file --
+
+This will expand to the following equivalent job file at runtime:
+
+; -- start job file --
+[random-writers]
+rw=randwrite
+size=64m
+numjobs=4
+; -- end job file --
+
fio ships with a few example job files, you can also look there for
inspiration.
str String. This is a sequence of alpha characters.
int Integer. A whole number value, can be negative. If prefixed with
0x, the integer is assumed to be of base 16 (hexadecimal).
+time Integer with possible time postfix. In seconds unless otherwise
+ specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds,
+ minutes, and hours.
siint SI integer. A whole number value, which may contain a postfix
describing the base of the number. Accepted postfixes are k/m/g,
meaning kilo, mega, and giga. So if you want to specify 4096,
the allowed CPUs to be 1 and 5, you would pass the decimal
value of (1 << 1 | 1 << 5), or 34. See man
sched_setaffinity(2). This may not work on all supported
- operating systems or kernel versions.
+ operating systems or kernel versions. This option doesn't
+ work well for a higher CPU count than what you can store in
+ an integer mask, so it can only control cpus 1-32. For
+ boxes with larger CPU counts, use cpus_allowed.
cpus_allowed=str Controls the same options as cpumask, but it allows a text
setting of the permitted CPUs instead. So to use CPUs 1 and
- 5, you would specify cpus_allowed=1,5.
+ 5, you would specify cpus_allowed=1,5. This options also
+ allows a range of CPUs. Say you wanted a binding to CPUs
+ 1, 5, and 8-15, you would set cpus_allowed=1,5,8-15.
-startdelay=int Start this job the specified number of seconds after fio
+startdelay=time Start this job the specified number of seconds after fio
has started. Only useful if the job file contains several
jobs, and you want to delay starting some jobs to a certain
time.
-runtime=int Tell fio to terminate processing after the specified number
+runtime=time Tell fio to terminate processing after the specified number
of seconds. It can be quite hard to determine for how long
a specified job will run, so this parameter is handy to
cap the total runtime to a given time.
written. It will simply loop over the same workload
as many times as the runtime allows.
-ramp_time If set, fio will run the specified workload for this amount
+ramp_time=time If set, fio will run the specified workload for this amount
of time before logging any performance numbers. Useful for
letting performance settle before logging results, thus
- minimizing the runtime required for stable results.
+ minimizing the runtime required for stable results. Note
+ that the ramp_time is considered lead in time for a job,
+ thus it will increase the total runtime if a special timeout
+ or runtime is specified.
invalidate=bool Invalidate the buffer/page cache parts for this file prior
to starting io. Defaults to true.
the file needs to be turned into a blkparse binary data
file first (blktrace <device> -d file_for_fio.bin).
-write_bw_log If given, write a bandwidth log of the jobs in this job
+write_bw_log=str If given, write a bandwidth log of the jobs in this job
file. Can be used to store data of the bandwidth of the
jobs in their lifetime. The included fio_generate_plots
script uses gnuplot to turn these text files into nice
- graphs.
+ graphs. See write_log_log for behaviour of given
+ filename. For this option, the postfix is _bw.log.
+
+write_lat_log=str Same as write_bw_log, except that this option stores io
+ completion latencies instead. If no filename is given
+ with this option, the default filename of "jobname_type.log"
+ is used. Even if the filename is given, fio will still
+ append the type of log. So if one specifies
+
+ write_lat_log=foo
-write_lat_log Same as write_bw_log, except that this option stores io
- completion latencies instead.
+ The actual log names will be foo_clat.log and foo_slat.log.
+ This helps fio_generate_plot fine the logs automatically.
lockmem=siint Pin down the specified amount of memory with mlock(2). Can
potentially be used instead of removing memory or booting
disk_util=bool Generate disk utilization statistics, if the platform
supports it. Defaults to on.
+disable_clat=bool Disable measurements of completion latency numbers. Useful
+ only for cutting back the number of calls to gettimeofday,
+ as that does impact performance at really high IOPS rates.
+ Note that to really get rid of a large amount of these
+ calls, this option must be used with disable_slat and
+ disable_bw as well.
+
+disable_slat=bool Disable measurements of submission latency numbers. See
+ disable_clat.
+
+disable_bw=bool Disable measurements of throughput/bandwidth numbers. See
+ disable_clat.
+
+gtod_reduce=bool Enable all of the gettimeofday() reducing options
+ (disable_clat, disable_slat, disable_bw) plus reduce
+ precision of the timeout somewhat to really shrink
+ the gettimeofday() call count. With this option enabled,
+ we only do about 0.4% of the gtod() calls we would have
+ done if all time keeping was enabled.
+
6.0 Interpreting the output
---------------------------
client1;0;0;1906777;1090804;1790;0;0;0.000000;0.000000;0;0;0.000000;0.000000;929380;1152890;25.510151%;1078276.333333;128948.113404;0;0;0;0;0;0.000000;0.000000;0;0;0.000000;0.000000;0;0;0.000000%;0.000000;0.000000;100.000000%;0.000000%;324;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%;0.0%;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%
;0.0%;0.0%;0.0%;0.0%;0.0%
+To enable terse output, use the --minimal command line option.
+
Split up, the format is as follows:
jobname, groupid, error
projects / fio.git / blobdiff