X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=README;h=480f1d0ef6d455efa1e49c672def112b0607e6c1;hp=8b84a08a8d8583ce2e24b03dc74947f565e40b84;hb=26eca2db3ef6e92ff1022099cb89fc8ce88ee15d;hpb=c04f7ec3ecb8ce780bde6ad3515f003e6015c62a diff --git a/README b/README index 8b84a08a..480f1d0e 100644 --- a/README +++ b/README @@ -1,10 +1,12 @@ 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 @@ -12,44 +14,187 @@ 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 has fio RPMs in his repository for +SUSE variants, you can find them here: -Options -------- +http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio -$ fio - -s IO is sequential - -b block size in KiB for each io - -t Runtime in seconds - -r For random io, sequence must be repeatable - -R If one thread fails to meet rate, quit all - -o Use direct IO is 1, buffered if 0 - -l Generate per-job latency logs - -w Generate per-job bandwidth logs - -f Read for job descriptions - -h Print help info - -v Print version information and exit - -The format is as follows: +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, and development - 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@vger.kernel.org, subscribe by sending an email to +majordomo@vger.kernel.org with + +subscribe fio + +in the body of the email. There is no archive for the new list yet, +archives for the old list can be found here: + +http://maillist.kernel.dk/fio-devel/ + + +Building +-------- + +Just type 'make' and 'make install'. If on FreeBSD, for now you have to +specify the FreeBSD Makefile with -f and use gmake (not make), eg: + +$ gmake -f Makefile.Freebsd && gmake -f Makefile.FreeBSD install +Likewise with OpenSolaris, use the Makefile.solaris to compile there. +The OpenSolaris make should work fine. This might change in the +future if I opt for an autoconf type setup. + +If your compile fails with an error like this: + + CC gettime.o +In file included from fio.h:23, + from gettime.c:8: +os/os.h:15:20: error: libaio.h: No such file or directory +In file included from gettime.c:8: +fio.h:119: error: field 'iocb' has incomplete type +make: *** [gettime.o] Error 1 + +Check that you have the libaio development package installed. On RPM +based distros, it's typically called libaio-devel. + + +Command line +------------ + +$ fio + --debug Enable some debugging options (see below) + --output Write output to file + --timeout 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, preventing writes + --eta=when When ETA estimate should be printed + May be "always", "never" or "auto" + --section=name Only run specified section in job file + --alloc-size=kb Set smalloc pool to this size in kb (def 1024) + + +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 + blktrace Dump info related to blktrace setup + verify Dump info related to IO verification + all Enable all debug options + random Dump info related to random offset generation + parse Dump info related to option matching and parsing + diskutil Dump info related to disk utilization updates + job:x Dump info only related to job number x + mutex Dump info only related to mutex up/down ops + ? or help Show available debug options. + +You can specify as many as you want, eg --debug=file,mem will enable +file and memory debugging. + +The section switch is meant to make it easier to ship a bigger job file +instead of several smaller ones. Say you define a job file with light, +moderate, and heavy parts. Then you can ask fio to run the given part +only by giving it a --section=heavy command line option. The section +option only applies to job sections, the reserved 'global' section is +always parsed and taken into account. + +Fio has an internal allocator for shared memory called smalloc. It +allocates shared structures from this pool. The pool defaults to 1024k +in size, and can grow to 128 pools. If running large jobs with randommap +enabled it can run out of memory, in which case the --alloc-size switch +is handy for starting with a larger pool size. The backing store is +files in /tmp. Fio cleans up after itself, while it is running you +may see .fio_smalloc.* files in /tmp. + + +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, - 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. + posixaio for POSIX aio, solarisaio for Solaris + native async IO, sync for regular read/write io, + psync for regular pread/pwrite io, vsync for regular + readv/writev (with queuing emulation) mmap for mmap'ed + io, syslet-rw for syslet driven read/write, splice for + using splice/vmsplice, sg for direct SG_IO io, net + for network io, or cpuio for a cycler burner load. sg + 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. @@ -61,23 +206,30 @@ The format is as follows: 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 a lot faster. Only makes sense for writing to a file. + For other types of checksumming, see HOWTO. 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 @@ -92,142 +244,58 @@ The format is as follows: 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. + -Examples using a job file -------------------------- - -A sample job file doing the same as above would look like this: -[read_file] -rw=0 -bs=4096 +Platforms +--------- -[write_file] -rw=1 -bs=16384 +Fio works on (at least) Linux, Solaris, and FreeBSD. Some features and/or +options may only be available on some of the platforms, typically because +those features only apply to that platform (like the solarisaio engine, or +the splice engine on Linux). -And fio would be invoked as: +Some features are not available on FreeBSD/Solaris even if they could be +implemented, I'd be happy to take patches for that. An example of that is +disk utility statistics and (I think) huge page support, support for that +does exist in FreeBSD/Solaris. -$ fio -o1 -s -f file_with_above +Fio uses pthread mutexes for signalling and locking and FreeBSD does not +support process shared pthread mutexes. As a result, only threads are +supported on FreeBSD. This could be fixed with sysv ipc locking or +other locking alternatives. -The second example would look like this: - -[rf1] -rw=0 -prio=6 +Other *BSD platforms are untested, but fio should work there almost out +of the box. Since I don't do test runs or even compiles on those platforms, +your mileage may vary. Sending me patches for other platforms is greatly +appreciated. There's a lot of value in having the same test/benchmark tool +available on all platforms. -[rf2] -rw=0 -prio=3 -[rf3] -rw=0 -prio=0 -direct=1 -And fio would be invoked as: +Author +------ + +Fio was written by Jens Axboe 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 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.