[disktools.git] / README.fio

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.

Options
-------

$ 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

The <jobs> format is as follows:

	rw=0/1		0 is read, 1 is write
	prio=x		Run io at prio X, 0-7 is the kernel allowed range
	prioclass=x	Run io at prio class X
	file=foo	Do the io to file foo
	bs=x		Thread blocksize is x bytes
	bsrange=x-y	Mix thread block sizes randomly between x and y
	direct=x	1 for direct IO, 0 for buffered IO
	thinktime=x	"Think" x usec after each io
	random		IO is randomized
	sequential	IO is sequential
	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	Allow job to run on CPUs defined by mask
	fsync=x		If writing, fsync after every x blocks have been written
	startdelay=x	Start this thread x seconds after startup
	timeout=x	Terminate x seconds after startup
	aio		Use Linux async io
	aio_depth=x	Allow x iocbs in flight
	size=x		Set file size to x bytes (x string can include k/m/g)
	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
	mem=x		If x == malloc, use malloc for buffers. If x == shm,
			use shm for buffers.
	exitall		When one thread quits, terminate the others
	bwavgtime=x	Average bandwidth stats over x msec
	create_serialize=x	If 'x', serialize file creation.
	create_fsync=x	If 'x', run fsync() after file creation.
	loops=x		Run the job 'x' number of times.


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

[rf3]
rw=0
prio=0
direct=1

And fio would be invoked as:

$ 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.
Commit	Line	Data
e709787c JA	1	fio
	2	---
	3
	4	fio is a tool that will spawn a number of thread doing a particular
	5	type of io action as specified by the user. fio takes a number of
	6	global parameters, each inherited by the thread unless otherwise
	7	parameters given to them overriding that setting is given.
	8
	9	Options
	10	-------
	11
	12	$ fio
	13	-s IO is sequential
86184d14	14	-b block size in KiB for each io
e709787c	15	-t <sec> Runtime in seconds
e709787c	16	-r For random io, sequence must be repeatable
02bdd9ba	17	-R <on> If one thread fails to meet rate, quit all
e709787c	18	-o <on> Use direct IO is 1, buffered if 0
a0a9b35b JA	19	-l Generate per-job latency logs
a0a9b35b JA	20	-w Generate per-job bandwidth logs
7dd1389e	21	-f <file> Read <file> for job descriptions
e709787c	22
e709787c JA	23	The <jobs> format is as follows:
	24
	25	rw=0/1 0 is read, 1 is write
	26	prio=x Run io at prio X, 0-7 is the kernel allowed range
	27	prioclass=x Run io at prio class X
	28	file=foo Do the io to file foo
8c033f93	29	bs=x Thread blocksize is x bytes
7889f07b	30	bsrange=x-y Mix thread block sizes randomly between x and y
e709787c	31	direct=x 1 for direct IO, 0 for buffered IO
e97712ed	32	thinktime=x "Think" x usec after each io
e709787c JA	33	random IO is randomized
e709787c JA	34	sequential IO is sequential
86184d14	35	rate=x Throttle rate to x KiB/sec
4240cfa1 JA	36	ratemin=x Quit if rate of x KiB/sec can't be met
4240cfa1 JA	37	ratecycle=x ratemin averaged over x msecs
18e0b78c	38	cpumask=x Allow job to run on CPUs defined by mask
4240cfa1	39	fsync=x If writing, fsync after every x blocks have been written
fc24389f	40	startdelay=x Start this thread x seconds after startup
67903a2e	41	timeout=x Terminate x seconds after startup
43000118 JA	42	aio Use Linux async io
43000118 JA	43	aio_depth=x Allow x iocbs in flight
02983297 JA	44	size=x Set file size to x bytes (x string can include k/m/g)
02983297 JA	45	offset=x Start io at offset x (x string can include k/m/g)
b95799ca	46	invalidate=x Invalidate page cache for file prior to doing io
74b4b5fb	47	sync=x Use sync writes if x and writing
99c6704f JA	48	mem=x If x == malloc, use malloc for buffers. If x == shm,
99c6704f JA	49	use shm for buffers.
98dd52d6	50	exitall When one thread quits, terminate the others
1d035750	51	bwavgtime=x Average bandwidth stats over x msec
b6794fbf JA	52	create_serialize=x If 'x', serialize file creation.
	53	create_fsync=x If 'x', run fsync() after file creation.
	54	loops=x Run the job 'x' number of times.
e709787c JA	55
e709787c JA	56
7dd1389e JA	57	Examples using a job file
	58	-------------------------
	59
	60	A sample job file doing the same as above would look like this:
	61
	62	[read_file]
	63	rw=0
	64	bs=4096
	65
	66	[write_file]
	67	rw=1
	68	bs=16384
	69
	70	And fio would be invoked as:
	71
	72	$ fio -o1 -s -f file_with_above
	73
	74	The second example would look like this:
	75
	76	[rf1]
	77	rw=0
	78	prio=6
	79
	80	[rf2]
	81	rw=0
	82	prio=3
	83
	84	[rf3]
	85	rw=0
	86	prio=0
	87	direct=1
	88
	89	And fio would be invoked as:
	90
	91	$ fio -o0 -s -b4096 -f file_with_above
	92
47d45203 JA	93	'global' is a reserved keyword. When used as the filename, it sets the
	94	default options for the threads following that section. It is possible
	95	to have more than one global section in the file, as it only affects
	96	subsequent jobs.
ed864e24 JA	97
ed864e24 JA	98	Also see the examples/ dir for sample job files.
47d45203	99