X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=README;h=059fead22a1ee530a17b15cff7b60bab8aefa2ba;hp=7e87c47b8ef8ea52940b0757884d4cf9164b2435;hb=6839616ff2ac013c8b0fbeb2a97f6cf20976b9f3;hpb=244e170ebd309303d124c57cde7bf7a3b40d09e7 diff --git a/README b/README index 7e87c47b..059fead2 100644 --- a/README +++ b/README @@ -57,13 +57,27 @@ $ 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. +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 - --runtime Runtime in seconds + --timeout Runtime in seconds --latency-log Generate per-job latency logs --bandwidth-log Generate per-job bandwidth logs --minimal Minimal (terse) output @@ -71,21 +85,65 @@ $ fio --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 + ? 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 32 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. + 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 +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 it's easy to read and write for the user. +is in the ini style format, as that is easy to read and write for the user. The job file parameters are: @@ -110,13 +168,16 @@ The job file parameters are: 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, 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. + 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,