Specifies when real-time ETA estimate should be printed. \fIwhen\fR may
be one of `always', `never' or `auto'.
.TP
+.BI \-\-section \fR=\fPsec
+Only run section \fIsec\fR from job file.
+.TP
.BI \-\-cmdhelp \fR=\fPcommand
Print help information for \fIcommand\fR. May be `all' for all commands.
.TP
+.BI \-\-debug \fR=\fPtype
+Enable verbose tracing of various fio actions. May be `all' for all types
+or individual types seperated by a comma (eg --debug=io,file). `help' will
+list all available tracing options.
+.TP
.B \-\-help
Display usage information and exit.
.TP
String: a sequence of alphanumeric characters.
.TP
.I int
-Integer: a whole number, possibly negative. If prefixed with `0x', the value
-is assumed to be base 16 (hexadecimal).
-.TP
-.I siint
SI integer: a whole number, possibly containing a suffix denoting the base unit
of the value. Accepted suffixes are `k', 'M' and 'G', denoting kilo (1024),
-mega (1024*1024) and giga (1024*1024*1024) respectively.
+mega (1024*1024) and giga (1024*1024*1024) respectively. If prefixed with '0x',
+the value is assumed to be base 16 (hexadecimal).
.TP
.I bool
Boolean: a true or false value. `0' denotes false, `1' denotes true.
Disable use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
are likely to be issued. Default: true.
.TP
-.BI size \fR=\fPsiint
+.BI size \fR=\fPint
Total size of I/O for this job. \fBfio\fR will run until this many bytes have
been transfered, unless limited by other options (\fBruntime\fR, for instance).
Unless \fBnr_files\fR and \fBfilesize\fR options are given, this amount will be
that is given). If \fBfilesize\fR is not specified, each created file is the
same size.
.TP
-.BI blocksize \fR=\fPsiint "\fR,\fB bs" \fR=\fPsiint
+.BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int]
Block size for I/O units. Default: 4k. Values for reads and writes can be
specified seperately in the format \fIread\fR,\fIwrite\fR, either of
which may be empty to leave that value at its default.
.TP
-.BI blocksize_range \fR=\fPirange "\fR,\fB bsrange" \fR=\fPirange
+.BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange]
Specify a range of I/O block sizes. The issued I/O unit will always be a
multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies
-to both reads and writes, but can be specified seperately (see \fBblocksize\fR).
+to both reads and writes if only one range is given, but can be specified
+seperately with a comma seperating the values. Example: bsrange=1k-4k,2k-8k.
+Also (see \fBblocksize\fR).
+.TP
+.BI bssplit \fR=\fPstr
+This option allows even finer grained control of the block sizes issued,
+not just even splits between them. With this option, you can weight various
+block sizes for exact control of the issued IO for a job that has mixed
+block sizes. The format of the option is bssplit=blocksize/percentage,
+optionally adding as many definitions as needed seperated by a colon.
+Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
+blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate
+splits to reads and writes. The format is identical to what the
+\fBbs\fR option accepts, the read and write parts are separated with a
+comma.
.TP
.B blocksize_unaligned\fR,\fP bs_unaligned
If set, any size in \fBblocksize_range\fR may be used. This typically won't
work with direct I/O, as that normally requires sector alignment.
.TP
+.BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int]
+At what boundary to align random IO offsets. Defaults to the same as 'blocksize'
+the minimum blocksize given. Minimum alignment is typically 512b
+for using direct IO, though it usually depends on the hardware block size.
+This option is mutually exclusive with using a random map for files, so it
+will turn off that option.
+.TP
.B zero_buffers
Initialise buffers with all zeros. Default: fill buffers with random data.
.TP
+.B refill_buffers
+If this option is given, fio will refill the IO buffers on every submit. The
+default is to only fill it at init time and reuse that data. Only makes sense
+if zero_buffers isn't specified, naturally. If data verification is enabled,
+refill_buffers is also automatically enabled.
+.TP
.BI nrfiles \fR=\fPint
Number of files to use for this job. Default: 1.
.TP
.TP
.B roundrobin
Round robin over open files (default).
+.B sequential
+Do each file in the set sequentially.
.RE
.P
The number of I/Os to issue before switching a new file can be specified by
.B psync
Basic \fIpread\fR\|(2) or \fIpwrite\fR\|(2) I/O.
.TP
+.B vsync
+Basic \fIreadv\fR\|(2) or \fIwritev\fR\|(2) I/O. Will emulate queuing by
+coalescing adjacents IOs into a single submission.
+.TP
.B libaio
Linux native asynchronous I/O.
.TP
If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
Default: true.
.TP
-.BI offset \fR=\fPsiint
+.BI offset \fR=\fPint
Offset in the file to start I/O. Data before the offset will not be touched.
.TP
.BI fsync \fR=\fPint
completely read or written. The same workload will be repeated as many times
as \fBruntime\fR allows.
.TP
+.BI ramp_time \fR=\fPint
+If set, fio will run the specified workload for this amount of time before
+logging any performance numbers. Useful for letting performance settle before
+logging results, thus minimizing the runtime required for stable results. Note
+that the ramp_time is considered lead in time for a job, thus it will increase
+the total runtime if a special timeout or runtime is specified.
+.TP
.BI invalidate \fR=\fPbool
Invalidate buffer-cache for the file prior to starting I/O. Default: true.
.TP
have hugetlbfs mounted, and \fIfile\fR must point there.
.RE
.TP
-.BI hugepage\-size \fR=\fPsiint
+.BI hugepage\-size \fR=\fPint
Defines the size of a huge page. Must be at least equal to the system setting.
Should be a multiple of 1MiB. Default: 4MiB.
.TP
.BI create_fsync \fR=\fPbool
\fIfsync\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 unlink \fR=\fPbool
Unlink job files when done. Default: false.
.TP
If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
read them back in a sorted manner. Default: true.
.TP
-.BI verify_offset \fR=\fPsiint
+.BI verify_offset \fR=\fPint
Swap the verification header with data somewhere else in the block before
writing. It is swapped back before verifying.
.TP
-.BI verify_interval \fR=\fPsiint
+.BI verify_interval \fR=\fPint
Write the verification header for this number of bytes, which should divide
\fBblocksize\fR. Default: \fBblocksize\fR.
.TP
Use threads created with \fBpthread_create\fR\|(3) instead of processes created
with \fBfork\fR\|(2).
.TP
-.BI zonesize \fR=\fPsiint
+.BI zonesize \fR=\fPint
Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
.TP
-.BI zoneskip \fR=\fPsiint
+.BI zoneskip \fR=\fPint
Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
read.
.TP
Replay the I/O patterns contained in the specified file generated by
\fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
.TP
-.B write_bw_log
-If given, write bandwidth logs of the jobs in this file.
+.B write_bw_log \fR=\fPstr
+If given, write a bandwidth log of the jobs in this job file. Can be used to
+store data of the bandwidth of the jobs in their lifetime. The included
+fio_generate_plots script uses gnuplot to turn these text files into nice
+graphs. See \fBwrite_log_log\fR for behaviour of given filename. For this
+option, the postfix is _bw.log.
.TP
.B write_lat_log
-Same as \fBwrite_bw_log\fR, but writes I/O completion latencies.
+Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
+filename is given with this option, the default filename of "jobname_type.log"
+is used. Even if the filename is given, fio will still append the type of log.
+.TP
+.B disable_clat \fR=\fPbool
+Disable measurements of completion latency numbers. Useful only for cutting
+back the number of calls to gettimeofday, 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
-.BI lockmem \fR=\fPsiint
+.B disable_slat \fR=\fPbool
+Disable measurements of submission latency numbers. See \fBdisable_clat\fR.
+.TP
+.B disable_bw_measurement \fR=\fPbool
+Disable measurements of throughput/bandwidth numbers. See \fBdisable_clat\fR.
+.TP
+.BI lockmem \fR=\fPint
Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
simulate a smaller amount of memory.
.TP
.TP
.BI disk_util \fR=\fPbool
Generate disk utilization statistics if the platform supports it. Default: true.
+.TP
+.BI gtod_reduce \fR=\fPbool
+Enable all of the gettimeofday() 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
+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
+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
+these time calls will be excluded from other uses. Fio will manually clear it
+from the CPU mask of other jobs.
.SH OUTPUT
While running, \fBfio\fR will display the status of the created jobs. For
example:
.P
CPU usage:
.RS
-.B user, system, context switches
+.B user, system, context switches, major page faults, minor page faults
.RE
.P
IO depth distribution:
This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
on documentation by Jens Axboe.
.SH "REPORTING BUGS"
-Report bugs to the \fBfio\fR mailing list <fio-devel@kernel.dk>.
+Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
See \fBREADME\fR.
.SH "SEE ALSO"
For further documentation see \fBHOWTO\fR and \fBREADME\fR.
projects / fio.git / blobdiff