README - platform/external/fio - Gitiles

 fio
 ---

 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://git.kernel.dk/fio.git

 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 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/

 Mandriva has integrated fio into their package repository, so installing
 on that distro should be as easy as typing 'urpmi 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.


 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
         --debug         Enable some debugging options (see below)
         --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
 	--readonly	Turn on safety read-only checks
 	--eta=when	When ETA estimate should be printed
 			May be "always", "never" or "auto"


 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.

 The --readonly switch is an extra safety guard to prevent accidentically
 turning on a write setting when that is not desired. Fio will only write
 if rw=write/randwrite/rw/randrw is given, but this extra safety net can
 be used as an extra precaution. It will also enable a write check in the
 io engine core to prevent an accidental write due to a fio bug.

 The debug switch allows adding options that trigger certain logging
 options in fio. Currently the options are:

 	process		Dump info related to processes
 	file		Dump info related to file actions
 	io		Dump info related to IO queuing
 	mem		Dump info related to memory allocations

 You can specify as many as you want, eg --debug=file,mem will enable
 file and memory debugging. Specifying --debug=help or --debug=? will
 dump the current modifier list.


 Job file
 --------

 See the HOWTO file for a more detailed description of parameters and what
 they mean. This file contains the terse version. You can describe big and
 complex setups with the command line, but 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 that is 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
 			in msecs.
 	rwmixread=x	'x' percentage of rw mix ios will be reads. If
 			rwmixwrite is also given, the last of the two will
 			 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,
 			psync for regular pread/pwrite io, 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.
 	bsrange=x-y	Mix thread block sizes randomly between x and y. May
 			also include k/m postfix.
 	direct=x	1 for direct IO, 0 for buffered IO
 	thinktime=x	"Think" x usec after each io
 	rate=x		Throttle rate to x KiB/sec
 	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.
 	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
 	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 buffered IO.
 	mem=x		If x == malloc, use malloc for buffers. If x == shm,
 			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.
 	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
 			a lot faster. Only makes sense for writing to a file.
 	stonewall	Wait for preceeding jobs to end before running.
 	numjobs=x	Create 'x' similar entries for this job
 	thread		Use pthreads instead of forked jobs
 	zonesize=x
 	zoneskip=y	Zone options must be paired. If given, the job
 			will skip y bytes for every x read/written. This
 			can be used to gauge hard drive speed over the entire
 			platter, without reading everything. Both x/y can
 			include k/m/g suffix.
 	iolog=x		Open and read io pattern from file 'x'. The file must
 			contain one io action per line in the following format:
 			rw, offset, length
 			where with rw=0/1 for read/write, and the offset
 			and length entries being in bytes.
 	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.
 	nice=x		Run job at given nice value.
 	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.


 Author
 ------

 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.

 Jens Axboe <axboe@kernel.dk> 20060905
	fio
	---

	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://git.kernel.dk/fio.git

	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 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/

	Mandriva has integrated fio into their package repository, so installing
	on that distro should be as easy as typing 'urpmi 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.


	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
	--debug Enable some debugging options (see below)
	--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
	--readonly Turn on safety read-only checks
	--eta=when When ETA estimate should be printed
	May be "always", "never" or "auto"


	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.

	The --readonly switch is an extra safety guard to prevent accidentically
	turning on a write setting when that is not desired. Fio will only write
	if rw=write/randwrite/rw/randrw is given, but this extra safety net can
	be used as an extra precaution. It will also enable a write check in the
	io engine core to prevent an accidental write due to a fio bug.

	The debug switch allows adding options that trigger certain logging
	options in fio. Currently the options are:

	process Dump info related to processes
	file Dump info related to file actions
	io Dump info related to IO queuing
	mem Dump info related to memory allocations

	You can specify as many as you want, eg --debug=file,mem will enable
	file and memory debugging. Specifying --debug=help or --debug=? will
	dump the current modifier list.


	Job file
	--------

	See the HOWTO file for a more detailed description of parameters and what
	they mean. This file contains the terse version. You can describe big and
	complex setups with the command line, but 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 that is 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
	in msecs.
	rwmixread=x 'x' percentage of rw mix ios will be reads. If
	rwmixwrite is also given, the last of the two will
	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,
	psync for regular pread/pwrite io, 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.
	bsrange=x-y Mix thread block sizes randomly between x and y. May
	also include k/m postfix.
	direct=x 1 for direct IO, 0 for buffered IO
	thinktime=x "Think" x usec after each io
	rate=x Throttle rate to x KiB/sec
	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.
	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
	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 buffered IO.
	mem=x If x == malloc, use malloc for buffers. If x == shm,
	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.
	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
	a lot faster. Only makes sense for writing to a file.
	stonewall Wait for preceeding jobs to end before running.
	numjobs=x Create 'x' similar entries for this job
	thread Use pthreads instead of forked jobs
	zonesize=x
	zoneskip=y Zone options must be paired. If given, the job
	will skip y bytes for every x read/written. This
	can be used to gauge hard drive speed over the entire
	platter, without reading everything. Both x/y can
	include k/m/g suffix.
	iolog=x Open and read io pattern from file 'x'. The file must
	contain one io action per line in the following format:
	rw, offset, length
	where with rw=0/1 for read/write, and the offset
	and length entries being in bytes.
	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.
	nice=x Run job at given nice value.
	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.


	Author
	------

	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.

	Jens Axboe <axboe@kernel.dk> 20060905