Merge branch 'priorityQueuing' of https://github.com/Seagate/fio

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 6283fc1d92931fd860915c92735d0f9136c3ac7e..05896e61418e564461b98628c8a14462fe7c1a02 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -1795,12 +1795,12 @@ In addition, there are some parameters which are only valid when a specific
 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.
 .TP
 .BI (io_uring)fixedbufs
 If fio is asked to do direct IO, then Linux will map pages for each IO call, and
@@ -1808,6 +1808,13 @@ release them when IO is done. If this option is set, the pages are pre-mapped
 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
@@ -2386,10 +2393,14 @@ priority class.
 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