specified, but lets all clones use the same file if set).
.RS
.P
-See the \fBfilename\fR option for information on how to escape ':' and '\\'
+See the \fBfilename\fR option for information on how to escape ':'
characters within the directory path itself.
.P
Note: To control the directory fio will use for internal state files
explicit size is specified by \fBfilesize\fR.
.RS
.P
-Each colon and backslash in the wanted path must be escaped with a '\\'
+Each colon in the wanted path must be escaped with a '\\'
character. For instance, if the path is `/dev/dsk/foo@3,0:c' then you
would use `filename=/dev/dsk/foo@3,0\\:c' and if the path is
-`F:\\filename' then you would use `filename=F\\:\\\\filename'.
+`F:\\filename' then you would use `filename=F\\:\\filename'.
.P
On Windows, disk devices are accessed as `\\\\.\\PhysicalDrive0' for
the first device, `\\\\.\\PhysicalDrive1' for the second etc.
.RS
.TP
.B none
-The \fBzonerange\fR, \fBzonesize\fR and \fBzoneskip\fR parameters are ignored.
+The \fBzonerange\fR, \fBzonesize\fR \fBzonecapacity\fR and \fBzoneskip\fR
+parameters are ignored.
.TP
.B strided
I/O happens in a single zone until \fBzonesize\fR bytes have been transferred.
After that number of bytes has been transferred processing of the next zone
-starts.
+starts. The \fBzonecapacity\fR parameter is ignored.
.TP
.B zbd
Zoned block device mode. I/O happens sequentially in each zone, even if random
device zone size. For a regular block device or file, the specified
\fBzonesize\fR must be at least 512B.
.TP
+.BI zonecapacity \fR=\fPint
+For \fBzonemode\fR=zbd, this defines the capacity of a single zone, which is
+the accessible area starting from the zone start address. This parameter only
+applies when using \fBzonemode\fR=zbd in combination with regular block devices.
+If not specified it defaults to the zone size. If the target device is a zoned
+block device, the zone capacity is obtained from the device information and this
+option is ignored.
+.TP
.BI zoneskip \fR=\fPint
For \fBzonemode\fR=strided, the number of bytes to skip after \fBzonesize\fR
bytes of data have been transferred.
When running a random write test across an entire drive many more zones will be
open than in a typical application workload. Hence this command line option
that allows to limit the number of open zones. The number of open zones is
-defined as the number of zones to which write commands are issued.
+defined as the number of zones to which write commands are issued by all
+threads/processes.
+.TP
+.BI job_max_open_zones \fR=\fPint
+Limit on the number of simultaneously opened zones per single thread/process.
.TP
.BI zone_reset_threshold \fR=\fPfloat
A number between zero and one that indicates the ratio of logical blocks with
character devices. This engine supports trim operations. The
sg engine includes engine specific options.
.TP
+.B libzbc
+Synchronous I/O engine for SMR hard-disks using the \fBlibzbc\fR
+library. The target can be either an sg character device or
+a block device file. This engine supports the zonemode=zbd zone
+operations.
+.TP
.B null
Doesn't transfer any data, just pretends to. This is mainly used to
exercise fio itself and for debugging/testing purposes.
\fBfilesize\fR so that all the accounting still occurs, but no actual I/O will be
done other than creating the file.
.TP
+.B filestat
+Simply do stat() and do no I/O to the file. You need to set 'filesize'
+and 'nrfiles', so that files will be created.
+This engine is to measure file lookup and meta data access.
+.TP
.B libpmem
Read and write using mmap I/O to a file on a filesystem
mounted with DAX on a persistent memory device through the PMDK
with the caveat that when used on the command line, they must come after the
\fBioengine\fR that defines them is selected.
.TP
-.BI (io_uring)hipri
-If this option is set, fio will attempt to use polled IO completions. Normal IO
-completions generate interrupts to signal the completion of IO, polled
-completions do not. Hence they are require active reaping by the application.
-The benefits are more efficient IO for high IOPS scenarios, and lower latencies
-for low queue depth IO.
+.BI (io_uring, libaio)cmdprio_percentage \fR=\fPint
+Set the percentage of I/O that will be issued with higher priority by setting
+the priority bit. Non-read I/O is likely unaffected by ``cmdprio_percentage``.
+This option cannot be used with the `prio` or `prioclass` options. For this
+option to set the priority bit properly, NCQ priority must be supported and
+enabled and `direct=1' option must be used. fio must also be run as the root
+user.
.TP
.BI (io_uring)fixedbufs
If fio is asked to do direct IO, then Linux will map pages for each IO call, and
before IO is started. This eliminates the need to map and release for each IO.
This is more efficient, and reduces the IO latency as well.
.TP
+.BI (io_uring)hipri
+If this option is set, fio will attempt to use polled IO completions. Normal IO
+completions generate interrupts to signal the completion of IO, polled
+completions do not. Hence they are require active reaping by the application.
+The benefits are more efficient IO for high IOPS scenarios, and lower latencies
+for low queue depth IO.
+.TP
.BI (io_uring)registerfiles
With this option, fio registers the set of files being used with the kernel.
This avoids the overhead of managing file counts in the kernel, making the
When hipri is set this determines the probability of a pvsync2 I/O being high
priority. The default is 100%.
.TP
+.BI (pvsync2,libaio,io_uring)nowait
+By default if a request cannot be executed immediately (e.g. resource starvation,
+waiting on locks) it is queued and the initiating process will be blocked until
+the required resource becomes free.
+This option sets the RWF_NOWAIT flag (supported from the 4.14 Linux kernel) and
+the call will return instantly with EAGAIN or a partial result rather than waiting.
+
+It is useful to also use \fBignore_error\fR=EAGAIN when using this option.
+Note: glibc 2.27, 2.28 have a bug in syscall wrappers preadv2, pwritev2.
+They return EOPNOTSUP instead of EAGAIN.
+
+For cached I/O, using this option usually means a request operates only with
+cached data. Currently the RWF_NOWAIT flag does not supported for cached write.
+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 (cpuio)cpuload \fR=\fPint
Attempt to use the specified percentage of CPU cycles. This is a mandatory
option when using cpuio I/O engine.
function. This can be useful when multiple paths exist between the
client and the server or in certain loopback configurations.
.TP
+.BI (filestat)stat_type \fR=\fPstr
+Specify stat system call type to measure lookup/getattr performance.
+Default is \fBstat\fR for \fBstat\fR\|(2).
+.TP
.BI (sg)readfua \fR=\fPbool
With readfua option set to 1, read operations include the force
unit access (fua) flag. Default: 0.
defaults to 100.0, meaning that all I/Os must be equal or below to the value
set by \fBlatency_target\fR.
.TP
+.BI latency_run \fR=\fPbool
+Used with \fBlatency_target\fR. If false (default), fio will find the highest
+queue depth that meets \fBlatency_target\fR and exit. If true, fio will continue
+running and try to meet \fBlatency_target\fR by adjusting queue depth.
+.TP
.BI max_latency \fR=\fPtime
If set, fio will exit the job with an ETIMEDOUT error if it exceeds this
maximum latency. When the unit is omitted, the value is interpreted in
replay, the file needs to be turned into a blkparse binary data file first
(`blkparse <device> \-o /dev/null \-d file_for_fio.bin').
You can specify a number of files by separating the names with a ':' character.
-See the \fBfilename\fR option for information on how to escape ':' and '\'
+See the \fBfilename\fR option for information on how to escape ':'
characters within the file names. These files will be sequentially assigned to
job clones created by \fBnumjobs\fR.
.TP
Set the I/O priority value of this job. Linux limits us to a positive value
between 0 and 7, with 0 being the highest. See man
\fBionice\fR\|(1). Refer to an appropriate manpage for other operating
-systems since meaning of priority may differ.
+systems since meaning of priority may differ. For per-command priority
+setting, see I/O engine specific `cmdprio_percentage` and `hipri_percentage`
+options.
.TP
.BI prioclass \fR=\fPint
-Set the I/O priority class. See man \fBionice\fR\|(1).
+Set the I/O priority class. See man \fBionice\fR\|(1). For per-command
+priority setting, see I/O engine specific `cmdprio_percentage` and `hipri_percent`
+options.
.TP
.BI cpus_allowed \fR=\fPstr
Controls the same options as \fBcpumask\fR, but accepts a textual
Disable measurements of throughput/bandwidth numbers. See
\fBdisable_lat\fR.
.TP
+.BI slat_percentiles \fR=\fPbool
+Report submission latency percentiles. Submission latency is not recorded
+for synchronous ioengines.
+.TP
.BI clat_percentiles \fR=\fPbool
-Enable the reporting of percentiles of completion latencies. This option is
-mutually exclusive with \fBlat_percentiles\fR.
+Report completion latency percentiles.
.TP
.BI lat_percentiles \fR=\fPbool
-Enable the reporting of percentiles of I/O latencies. This is similar to
-\fBclat_percentiles\fR, except that this includes the submission latency.
-This option is mutually exclusive with \fBclat_percentiles\fR.
+Report total latency percentiles. Total latency is the sum of submission
+latency and completion latency.
.TP
.BI percentile_list \fR=\fPfloat_list
-Overwrite the default list of percentiles for completion latencies and the
-block error histogram. Each number is a floating number in the range
+Overwrite the default list of percentiles for latencies and the
+block error histogram. Each number is a floating point number in the range
(0,100], and the maximum length of the list is 20. Use ':' to separate the
-numbers, and list the numbers in ascending order. For example,
-`\-\-percentile_list=99.5:99.9' will cause fio to report the values of
-completion latency below which 99.5% and 99.9% of the observed latencies
-fell, respectively.
+numbers. For example, `\-\-percentile_list=99.5:99.9' will cause fio to
+report the latency durations below which 99.5% and 99.9% of the observed
+latencies fell, respectively.
.TP
.BI significant_figures \fR=\fPint
If using \fB\-\-output\-format\fR of `normal', set the significant figures
and IOPS. The logs share a common format, which looks like this:
.RS
.P
-time (msec), value, data direction, block size (bytes), offset (bytes)
+time (msec), value, data direction, block size (bytes), offset (bytes),
+command priority
.RE
.P
`Time' for the log entry is always in milliseconds. The `value' logged depends
from the start of the file for that particular I/O. The logging of the offset can be
toggled with \fBlog_offset\fR.
.P
+`Command priority` is 0 for normal priority and 1 for high priority. This is controlled
+by the ioengine specific \fBcmdprio_percentage\fR.
+.P
Fio defaults to logging every individual I/O but when windowed logging is set
through \fBlog_avg_msec\fR, either the average (by default) or the maximum
(\fBlog_max_value\fR is set) `value' seen over the specified period of time
projects / fio.git / blobdiff