.SS "Time related parameters"
.TP
.BI runtime \fR=\fPtime
-Tell fio to terminate processing after the specified period of time. It
-can be quite hard to determine for how long a specified job will run, so
-this parameter is handy to cap the total runtime to a given time. When
-the unit is omitted, the value is interpreted in seconds.
+Limit runtime. The test will run until it completes the configured I/O
+workload or until it has run for this specified amount of time, whichever
+occurs first. It can be quite hard to determine for how long a specified
+job will run, so this parameter is handy to cap the total runtime to a
+given time. When the unit is omitted, the value is interpreted in
+seconds.
.TP
.BI time_based
If set, fio will run for the duration of the \fBruntime\fR specified
OpenBSD and ZFS on Solaris don't support direct I/O. On Windows the synchronous
ioengines don't support direct I/O. Default: false.
.TP
-.BI atomic \fR=\fPbool
-If value is true, attempt to use atomic direct I/O. Atomic writes are
-guaranteed to be stable once acknowledged by the operating system. Only
-Linux supports O_ATOMIC right now.
-.TP
.BI buffered \fR=\fPbool
If value is true, use buffered I/O. This is the opposite of the
\fBdirect\fR option. Defaults to true.
.RE
.TP
.BI randrepeat \fR=\fPbool
-Seed the random number generator used for random I/O patterns in a
-predictable way so the pattern is repeatable across runs. Default: true.
+Seed all random number generators in a predictable way so the pattern is
+repeatable across runs. Default: true.
.TP
.BI allrandrepeat \fR=\fPbool
-Seed all random number generators in a predictable way so results are
-repeatable across runs. Default: false.
+Alias for \fBrandrepeat\fR. Default: true.
.TP
.BI randseed \fR=\fPint
Seed the random number generators based on this seed value, to be able to
.TP
.B random
Advise using FADV_RANDOM.
+.TP
+.B noreuse
+Advise using FADV_NOREUSE. This may be a no-op on older Linux
+kernels. Since Linux 6.3, it provides a hint to the LRU algorithm.
+See the \fBposix_fadvise\fR\|(2) man page.
.RE
.RE
.TP
before overwriting. The \fBtrimwrite\fR mode works well for this
constraint.
.TP
-.B pmemblk
-Read and write using filesystem DAX to a file on a filesystem
-mounted with DAX on a persistent memory device through the PMDK
-libpmemblk library.
-.TP
.B dev\-dax
Read and write using device DAX to a persistent memory device (e.g.,
/dev/dax0.0) through the PMDK libpmem library.
For direct I/O, requests will only succeed if cache invalidation isn't required,
file blocks are fully allocated and the disk request could be issued immediately.
.TP
+.BI (io_uring_cmd)fdp \fR=\fPbool
+Enable Flexible Data Placement mode for write commands.
+.TP
+.BI (io_uring_cmd)fdp_pli \fR=\fPstr
+Select which Placement ID Index/Indicies this job is allowed to use for writes.
+By default, the job will cycle through all available Placement IDs, so use this
+to isolate these identifiers to specific jobs. If you want fio to use placement
+identifier only at indices 0, 2 and 5 specify, you would set `fdp_pli=0,2,5`.
+.TP
.BI (cpuio)cpuload \fR=\fPint
Attempt to use the specified percentage of CPU cycles. This is a mandatory
option when using cpuio I/O engine.
kind of thinktime setting was used. If this option is set, then fio will
ignore the thinktime and continue doing IO at the specified rate, instead of
entering a catch-up mode after thinktime is done.
+.TP
+.BI rate_cycle \fR=\fPint
+Average bandwidth for \fBrate\fR and \fBrate_min\fR over this number
+of milliseconds. Defaults to 1000.
.SS "I/O latency"
.TP
.BI latency_target \fR=\fPtime
maximum latency. When the unit is omitted, the value is interpreted in
microseconds. Comma-separated values may be specified for reads, writes,
and trims as described in \fBblocksize\fR.
-.TP
-.BI rate_cycle \fR=\fPint
-Average bandwidth for \fBrate\fR and \fBrate_min\fR over this number
-of milliseconds. Defaults to 1000.
.SS "I/O replay"
.TP
.BI write_iolog \fR=\fPstr
.TP
.BI steadystate_duration \fR=\fPtime "\fR,\fP ss_dur" \fR=\fPtime
A rolling window of this duration will be used to judge whether steady state
-has been reached. Data will be collected once per second. The default is 0
-which disables steady state detection. When the unit is omitted, the
-value is interpreted in seconds.
+has been reached. Data will be collected every \fBss_interval\fR. The default
+is 0 which disables steady state detection. When the unit is omitted, the value
+is interpreted in seconds.
.TP
.BI steadystate_ramp_time \fR=\fPtime "\fR,\fP ss_ramp" \fR=\fPtime
Allow the job to run for the specified duration before beginning data
collection for checking the steady state job termination criterion. The
default is 0. When the unit is omitted, the value is interpreted in seconds.
+.TP
+.BI steadystate_check_interval \fR=\fPtime "\fR,\fP ss_interval" \fR=\fPtime
+The values suring the rolling window will be collected with a period of this
+value. If \fBss_interval\fR is 30s and \fBss_dur\fR is 300s, 10 measurements
+will be taken. Default is 1s but that might not converge, especially for slower
+devices, so set this accordingly. When the unit is omitted, the value is
+interpreted in seconds.
.SS "Measurements and reporting"
.TP
.BI per_job_logs \fR=\fPbool
when fio created the I/O unit to completion of the I/O operation.
.TP
.B bw
-Bandwidth statistics based on samples. Same names as the xlat stats,
-but also includes the number of samples taken (\fIsamples\fR) and an
-approximate percentage of total aggregate bandwidth this thread
-received in its group (\fIper\fR). 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.
+Bandwidth statistics based on measurements from discrete intervals. Fio
+continuosly monitors bytes transferred and I/O operations completed. By default
+fio calculates bandwidth in each half-second interval (see \fBbwavgtime\fR)
+and reports descriptive statistics for the measurements here. Same names as the
+xlat stats, but also includes the number of samples taken (\fIsamples\fR) and an
+approximate percentage of total aggregate bandwidth this thread received in its
+group (\fIper\fR). 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.
.TP
.B iops
-IOPS statistics based on samples. Same names as \fBbw\fR.
+IOPS statistics based on measurements from discrete intervals.
+For details see the description for \fBbw\fR above. See
+\fBiopsavgtime\fR to control the duration of the intervals.
+Same values reported here as for \fBbw\fR except for percentage.
.TP
.B lat (nsec/usec/msec)
The distribution of I/O completion latencies. This is the time from when
projects / fio.git / blobdiff