fio
---
-fio is a tool that will spawn a number of thread doing a particular
-type of io action as specified by the user. fio takes a number of
-global parameters, each inherited by the thread unless otherwise
-parameters given to them overriding that setting is given.
+fio is a tool that will spawn a number of threads or processes doing a
+particular type of io action as specified by the user. fio takes a
+number of global parameters, each inherited by the thread unless
+otherwise parameters given to them overriding that setting is given.
+The typical use of fio is to write a job file matching the io load
+one wants to simulate.
Source
fio resides in a git repo, the canonical place is:
-git://brick.kernel.dk/data/git/fio.git
+git://git.kernel.dk/fio.git
-Snapshots are frequently generated as well and they include the git
-meta data as well. You can download them here:
+The http protocol also works, path is the same.
+
+Snapshots are frequently generated and they include the git meta data as
+well. You can download them here:
http://brick.kernel.dk/snaps/
-Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository, you
-can find them here:
+Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository for
+SUSE variants, you can find them here:
http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio
+Dag Wieërs has RPMs for Red Hat related distros, find them here:
+
+http://dag.wieers.com/rpm/packages/fio/
+
+
+Mailing list
+------------
+
+There's a mailing list associated with fio. It's meant for general
+discussion, bug reporting, questions - basically anything that has to
+do with fio. An automated mail detailing recent commits is automatically
+sent to the list at most daily. The list address is fio-devel@kernel.dk,
+subscribe by sending an empty email to fio-devel+subscribe@kernel.dk.
+
-Options
--------
+Building
+--------
+
+Just type 'make' and 'make install'. If on FreeBSD, for now you have to
+specify the FreeBSD Makefile with -f, eg:
+
+$ make -f Makefile.Freebsd && make -f Makefile.FreeBSD install
+
+Likewise with OpenSolaris, use the Makefile.solaris to compile there.
+This might change in the future if I opt for an autoconf type setup.
+
+
+Command line
+------------
$ fio
- -s IO is sequential
- -b block size in KiB for each io
- -t <sec> Runtime in seconds
- -r For random io, sequence must be repeatable
- -R <on> If one thread fails to meet rate, quit all
- -o <on> Use direct IO is 1, buffered if 0
- -l Generate per-job latency logs
- -w Generate per-job bandwidth logs
- -f <file> Read <file> for job descriptions
- -h Print help info
- -v Print version information and exit
-
-The <jobs> format is as follows:
+ --output Write output to file
+ --runtime Runtime in seconds
+ --latency-log Generate per-job latency logs
+ --bandwidth-log Generate per-job bandwidth logs
+ --minimal Minimal (terse) output
+ --version Print version info and exit
+ --help Print this page
+ --cmdhelp=cmd Print command help, "all" for all of them
+ --showcmd Turn a job file into command line options
+
+Any parameters following the options will be assumed to be job files,
+unless they match a job file parameter. You can add as many as you want,
+each job file will be regarded as a separate group and fio will stonewall
+its execution.
+
+
+Job file
+--------
+
+See the HOWTO file for a more detailed description of parameters and what
+they mean. This file contains the terse version. Only a few options can
+be controlled with command line parameters, generally it's a lot easier to
+just write a simple job file to describe the workload. The job file format
+is in the ini style format, as it's easy to read and write for the user.
+
+The job file parameters are:
name=x Use 'x' as the identifier for this job.
+ description=x 'x' is a text description of the job.
directory=x Use 'x' as the top level directory for storing files
+ filename=x Force the use of 'x' as the filename for all files
+ in this thread. If not given, fio will make up
+ a suitable filename based on the thread and file
+ number.
rw=x 'x' may be: read, randread, write, randwrite,
rw (read-write mix), randrw (read-write random mix)
rwmixcycle=x Base cycle for switching between read and write
be used if they don't add up to 100%.
rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
rwmixread.
+ rand_repeatable=x The sequence of random io blocks can be repeatable
+ across runs, if 'x' is 1.
size=x Set file size to x bytes (x string can include k/m/g)
ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
posixaio for POSIX aio, sync for regular read/write io,
- mmap for mmap'ed io, splice for using splice/vmsplice,
- or sgio for direct SG_IO io. The latter only works on
- Linux on SCSI (or SCSI-like devices, such as
- usb-storage or sata/libata driven) devices.
+ mmap for mmap'ed io, syslet-rw for syslet driven
+ read/write, splice for using splice/vmsplice,
+ sgio for direct SG_IO io, net for network io, or cpuio
+ for a cycler burner load. sgio only works on Linux on
+ SCSI (or SCSI-like devices, such as usb-storage or
+ sata/libata driven) devices. Fio also has a null io
+ engine, which is mainly used for testing fio itself.
iodepth=x For async io, allow 'x' ios in flight
overwrite=x If 'x', layout a write file first.
+ nrfiles=x Spread io load over 'x' number of files per job,
+ if possible.
prio=x Run io at prio X, 0-7 is the kernel allowed range
prioclass=x Run io at prio class X
bs=x Use 'x' for thread blocksize. May include k/m postfix.
ratemin=x Quit if rate of x KiB/sec can't be met
ratecycle=x ratemin averaged over x msecs
cpumask=x Only allow job to run on CPUs defined by mask.
- fsync=x If writing, fsync after every x blocks have been written
+ cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
+ fsync=x If writing with buffered IO, fsync after every
+ 'x' blocks have been written.
+ end_fsync=x If 'x', run fsync() after end-of-job.
startdelay=x Start this thread x seconds after startup
- timeout=x Terminate x seconds after startup
+ runtime=x Terminate x seconds after startup. Can include a
+ normal time suffix if not given in seconds, such as
+ 'm' for minutes, 'h' for hours, and 'd' for days.
offset=x Start io at offset x (x string can include k/m/g)
invalidate=x Invalidate page cache for file prior to doing io
- sync=x Use sync writes if x and writing
+ sync=x Use sync writes if x and writing buffered IO.
mem=x If x == malloc, use malloc for buffers. If x == shm,
- use shm for buffers. If x == mmap, use anon mmap.
+ use shared memory for buffers. If x == mmap, use
+ anonymous mmap.
exitall When one thread quits, terminate the others
bwavgtime=x Average bandwidth stats over an x msec window.
create_serialize=x If 'x', serialize file creation.
create_fsync=x If 'x', run fsync() after file creation.
- end_fsync=x If 'x', run fsync() after end-of-job.
+ unlink If set, unlink files when done.
loops=x Run the job 'x' number of times.
verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
use crc32 for verifies. md5 is 'safer', but crc32 is
write_iolog=x Write an iolog to file 'x' in the same format as iolog.
The iolog options are exclusive, if both given the
read iolog will be performed.
+ write_bw_log Write a bandwidth log.
+ write_lat_log Write a latency log.
lockmem=x Lock down x amount of memory on the machine, to
simulate a machine with less memory available. x can
include k/m/g suffix.
exec_prerun=x Run 'x' before job io is begun.
exec_postrun=x Run 'x' after job io has finished.
ioscheduler=x Use ioscheduler 'x' for this job.
+ cpuload=x For a CPU io thread, percentage of CPU time to attempt
+ to burn.
+ cpuchunks=x Split burn cycles into pieces of x usecs.
-Examples using a job file
--------------------------
-
-A sample job file doing the same as above would look like this:
-[read_file]
-rw=0
-bs=4096
-
-[write_file]
-rw=1
-bs=16384
-
-And fio would be invoked as:
-
-$ fio -o1 -s -f file_with_above
-
-The second example would look like this:
-
-[rf1]
-rw=0
-prio=6
-
-[rf2]
-rw=0
-prio=3
+Author
+------
-[rf3]
-rw=0
-prio=0
-direct=1
+Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
+of the Linux IO subsystem and schedulers. He got tired of writing
+specific test applications to simulate a given workload, and found that
+the existing io benchmark/test tools out there weren't flexible enough
+to do what he wanted.
-And fio would be invoked as:
+Jens Axboe <axboe@kernel.dk> 20060905
-$ fio -o0 -s -b4096 -f file_with_above
-
-'global' is a reserved keyword. When used as the filename, it sets the
-default options for the threads following that section. It is possible
-to have more than one global section in the file, as it only affects
-subsequent jobs.
-
-Also see the examples/ dir for sample job files.
-
-
-Interpreting the output
------------------------
-
-fio spits out a lot of output. While running, fio will display the
-status of the jobs created. An example of that would be:
-
-Threads now running: 2 : [ww] [5.73% done]
-
-The characters inside the square brackets denote the current status of
-each thread. The possible values (in typical life cycle order) are:
-
-Idle Run
----- ---
-P Thread setup, but not started.
-C Thread created and running, but not doing anything yet
- R Running, doing sequential reads.
- r Running, doing random reads.
- W Running, doing sequential writes.
- w Running, doing random writes.
-V Running, doing verification of written data.
-E Thread exited, not reaped by main thread yet.
-_ Thread reaped.
-
-The other values are fairly self explanatory - number of thread currently
-running and doing io, and the estimated completion percentage.
-
-When fio is done (or interrupted by ctrl-c), it will show the data for
-each thread, group of threads, and disks in that order. For each data
-direction, the output looks like:
-
-Client1 (g=0): err= 0:
- write: io= 32MiB, bw= 666KiB/s, runt= 50320msec
- slat (msec): min= 0, max= 136, avg= 0.03, dev= 1.92
- clat (msec): min= 0, max= 631, avg=48.50, dev=86.82
- bw (KiB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, dev=681.68
- cpu : usr=1.49%, sys=0.25%, ctx=7969
-
-The client number is printed, along with the group id and error of that
-thread. Below is the io statistics, here for writes. In the order listed,
-they denote:
-
-io= Number of megabytes io performed
-bw= Average bandwidth rate
-runt= The runtime of that thread
- slat= Submission latency (avg being the average, dev being the
- standard deviation). This is the time it took to submit
- the io. For sync io, the slat is really the completion
- latency, since queue/complete is one operation there.
- clat= Completion latency. Same names as slat, this denotes the
- time from submission to completion of the io pieces. For
- sync io, clat will usually be equal (or very close) to 0,
- as the time from submit to complete is basically just
- CPU time (io has already been done, see slat explanation).
- bw= Bandwidth. Same names as the xlat stats, but also includes
- an approximate percentage of total aggregate bandwidth
- this thread received in this group. This last value is
- only really useful if the threads in this group are on the
- same disk, since they are then competing for disk access.
-cpu= CPU usage. User and system time, along with the number
- of context switches this thread went through.
-
-After each client has been listed, the group statistics are printed. They
-will look like this:
-
-Run status group 0 (all jobs):
- READ: io=64MiB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec
- WRITE: io=64MiB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec
-
-For each data direction, it prints:
-
-io= Number of megabytes io performed.
-aggrb= Aggregate bandwidth of threads in this group.
-minb= The minimum average bandwidth a thread saw.
-maxb= The maximum average bandwidth a thread saw.
-mint= The minimum runtime of a thread.
-maxt= The maximum runtime of a thread.
-
-And finally, the disk statistics are printed. They will look like this:
-
-Disk stats (read/write):
- sda: ios=16398/16511, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00%
-
-Each value is printed for both reads and writes, with reads first. The
-numbers denote:
-
-ios= Number of ios performed by all groups.
-merge= Number of merges io the io scheduler.
-ticks= Number of ticks we kept the disk busy.
-io_queue= Total time spent in the disk queue.
-util= The disk utilization. A value of 100% means we kept the disk
- busy constantly, 50% would be a disk idling half of the time.
projects / fio.git / blobdiff