-.TH fio 1 "September 2007" "User Manual"
+.TH fio 1 "October 2013" "User Manual"
.SH NAME
fio \- flexible I/O tester
.SH SYNOPSIS
Do not pre-allocate space.
.TP
.B posix
-Pre-allocate via posix_fallocate().
+Pre-allocate via \fBposix_fallocate\fR\|(3).
.TP
.B keep
-Pre-allocate via fallocate() with FALLOC_FL_KEEP_SIZE set.
+Pre-allocate via \fBfallocate\fR\|(2) with FALLOC_FL_KEEP_SIZE set.
.TP
.B 0
Backward-compatible alias for 'none'.
.RE
.TP
.BI fadvise_hint \fR=\fPbool
-Use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
+Use of \fBposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
are likely to be issued. Default: true.
.TP
.BI size \fR=\fPint
.RS
.TP
.B sync
-Basic \fIread\fR\|(2) or \fIwrite\fR\|(2) I/O. \fIfseek\fR\|(2) is used to
+Basic \fBread\fR\|(2) or \fBwrite\fR\|(2) I/O. \fBfseek\fR\|(2) is used to
position the I/O location.
.TP
.B psync
-Basic \fIpread\fR\|(2) or \fIpwrite\fR\|(2) I/O.
+Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O.
.TP
.B vsync
-Basic \fIreadv\fR\|(2) or \fIwritev\fR\|(2) I/O. Will emulate queuing by
+Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate queuing by
coalescing adjacent IOs into a single submission.
.TP
.B pvsync
-Basic \fIpreadv\fR\|(2) or \fIpwritev\fR\|(2) I/O.
+Basic \fBpreadv\fR\|(2) or \fBpwritev\fR\|(2) I/O.
.TP
.B libaio
Linux native asynchronous I/O. This ioengine defines engine specific options.
.TP
.B posixaio
-POSIX asynchronous I/O using \fIaio_read\fR\|(3) and \fIaio_write\fR\|(3).
+POSIX asynchronous I/O using \fBaio_read\fR\|(3) and \fBaio_write\fR\|(3).
.TP
.B solarisaio
Solaris native asynchronous I/O.
Windows native asynchronous I/O.
.TP
.B mmap
-File is memory mapped with \fImmap\fR\|(2) and data copied using
-\fImemcpy\fR\|(3).
+File is memory mapped with \fBmmap\fR\|(2) and data copied using
+\fBmemcpy\fR\|(3).
.TP
.B splice
-\fIsplice\fR\|(2) is used to transfer the data and \fIvmsplice\fR\|(2) to
+\fBsplice\fR\|(2) is used to transfer the data and \fBvmsplice\fR\|(2) to
transfer data from user-space to the kernel.
.TP
.B syslet-rw
.TP
.B sg
SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
-the target is an sg character device, we use \fIread\fR\|(2) and
-\fIwrite\fR\|(2) for asynchronous I/O.
+the target is an sg character device, we use \fBread\fR\|(2) and
+\fBwrite\fR\|(2) for asynchronous I/O.
.TP
.B null
Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR
This ioengine defines engine specific options.
.TP
.B netsplice
-Like \fBnet\fR, but uses \fIsplice\fR\|(2) and \fIvmsplice\fR\|(2) to map data
+Like \fBnet\fR, but uses \fBsplice\fR\|(2) and \fBvmsplice\fR\|(2) to map data
and send/receive. This ioengine defines engine specific options.
.TP
.B cpuio
Make every Nth write a barrier write.
.TP
.BI sync_file_range \fR=\fPstr:int
-Use sync_file_range() for every \fRval\fP number of write operations. Fio will
-track range of writes that have happened since the last sync_file_range() call.
+Use \fBsync_file_range\fR\|(2) for every \fRval\fP number of write operations. Fio will
+track range of writes that have happened since the last \fBsync_file_range\fR\|(2) call.
\fRstr\fP can currently be one or more of:
.RS
.TP
.P
So if you do sync_file_range=wait_before,write:8, fio would use
\fBSYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE\fP for every 8 writes.
-Also see the sync_file_range(2) man page. This option is Linux specific.
+Also see the \fBsync_file_range\fR\|(2) man page. This option is Linux specific.
.TP
.BI overwrite \fR=\fPbool
If writing, setup the file first and do overwrites. Default: false.
workload, fio may read or write some blocks multiple times.
.TP
.BI nice \fR=\fPint
-Run job with given nice value. See \fInice\fR\|(2).
+Run job with given nice value. See \fBnice\fR\|(2).
.TP
.BI prio \fR=\fPint
Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
-\fIionice\fR\|(1).
+\fBionice\fR\|(1).
.TP
.BI prioclass \fR=\fPint
-Set I/O priority class. See \fIionice\fR\|(1).
+Set I/O priority class. See \fBionice\fR\|(1).
.TP
.BI thinktime \fR=\fPint
Stall job for given number of microseconds between issuing I/Os.
.RS
.TP
.B malloc
-Allocate memory with \fImalloc\fR\|(3).
+Allocate memory with \fBmalloc\fR\|(3).
.TP
.B shm
-Use shared memory buffers allocated through \fIshmget\fR\|(2).
+Use shared memory buffers allocated through \fBshmget\fR\|(2).
.TP
.B shmhuge
Same as \fBshm\fR, but use huge pages as backing.
.TP
.B mmap
-Use \fImmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
+Use \fBmmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
is given after the option in the format `:\fIfile\fR'.
.TP
.B mmaphuge
If true, serialize file creation for the jobs. Default: true.
.TP
.BI create_fsync \fR=\fPbool
-\fIfsync\fR\|(2) data file after creation. Default: true.
+\fBfsync\fR\|(2) data file after creation. Default: true.
.TP
.BI create_on_open \fR=\fPbool
If true, the files are not created until they are opened for IO by the job.
.TP
.BI disable_lat \fR=\fPbool
Disable measurements of total latency numbers. Useful only for cutting
-back the number of calls to gettimeofday, as that does impact performance at
+back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
really high IOPS rates. Note that to really get rid of a large amount of these
calls, this option must be used with disable_slat and disable_bw as well.
.TP
.RS
.TP
.B gettimeofday
-gettimeofday(2)
+\fBgettimeofday\fR\|(2)
.TP
.B clock_gettime
-clock_gettime(2)
+\fBclock_gettime\fR\|(2)
.TP
.B cpu
Internal CPU clock source
means supporting TSC Invariant.
.TP
.BI gtod_reduce \fR=\fPbool
-Enable all of the gettimeofday() reducing options (disable_clat, disable_slat,
+Enable all of the \fBgettimeofday\fR\|(2) reducing options (disable_clat, disable_slat,
disable_bw) plus reduce precision of the timeout somewhat to really shrink the
-gettimeofday() call count. With this option enabled, we only do about 0.4% of
+\fBgettimeofday\fR\|(2) call count. With this option enabled, we only do about 0.4% of
the gtod() calls we would have done if all time keeping was enabled.
.TP
.BI gtod_cpu \fR=\fPint
Sometimes it's cheaper to dedicate a single thread of execution to just getting
the current time. Fio (and databases, for instance) are very intensive on
-gettimeofday() calls. With this option, you can set one CPU aside for doing
+\fBgettimeofday\fR\|(2) calls. With this option, you can set one CPU aside for doing
nothing but logging current time to a shared memory location. Then the other
threads/processes that run IO workloads need only copy that segment, instead of
-entering the kernel with a gettimeofday() call. The CPU set aside for doing
+entering the kernel with a \fBgettimeofday\fR\|(2) call. The CPU set aside for doing
these time calls will be excluded from other uses. Fio will manually clear it
from the CPU mask of other jobs.
.TP
.BI 1:
allocate space immediately inside defragment event, and free right after event
.RE
-.TP
.SH OUTPUT
While running, \fBfio\fR will display the status of the created jobs. For
example:
projects / fio.git / blobdiff