Merge branch 'evelu-peak' of https://github.com/ErwanAliasr1/fio

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 9bfd38b4589610a5e9d7662fe321fa530222cbfd..297a04851a2bbb747d9c3b8e6df0143be45203a2 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -2163,14 +2163,49 @@ 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
 :option:`ioengine` that defines them is selected.
 
 with the caveat that when used on the command line, they must come after the
 :option:`ioengine` that defines them is selected.
 

-.. option:: cmdprio_percentage=int : [io_uring] [libaio]
-
-    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 :option:`direct`\=1 option must be used. fio must also be run as
-    the root user.
+.. option:: cmdprio_percentage=int[,int] : [io_uring] [libaio]
+
+    Set the percentage of I/O that will be issued with the highest priority.
+    Default: 0. A single value applies to reads and writes. Comma-separated
+    values may be specified for reads and writes. This option cannot be used
+    with the :option:`prio` or :option:`prioclass` options. For this option
+    to be effective, NCQ priority must be supported and enabled, and `direct=1'
+    option must be used. fio must also be run as the root user.
+
+.. option:: cmdprio_class=int[,int] : [io_uring] [libaio]
+
+       Set the I/O priority class to use for I/Os that must be issued with
+       a priority when :option:`cmdprio_percentage` or
+       :option:`cmdprio_bssplit` is set. If not specified when
+       :option:`cmdprio_percentage` or :option:`cmdprio_bssplit` is set,
+       this defaults to the highest priority class. A single value applies
+       to reads and writes. Comma-separated values may be specified for
+       reads and writes. See :manpage:`ionice(1)`. See also the
+       :option:`prioclass` option.
+
+.. option:: cmdprio=int[,int] : [io_uring] [libaio]
+
+       Set the I/O priority value to use for I/Os that must be issued with
+       a priority when :option:`cmdprio_percentage` or
+       :option:`cmdprio_bssplit` is set. If not specified when
+       :option:`cmdprio_percentage` or :option:`cmdprio_bssplit` is set,
+       this defaults to 0.
+       Linux limits us to a positive value between 0 and 7, with 0 being the
+       highest. A single value applies to reads and writes. Comma-separated
+       values may be specified for reads and writes. See :manpage:`ionice(1)`.
+       Refer to an appropriate manpage for other operating systems since
+       meaning of priority may differ. See also the :option:`prio` option.
+
+.. option:: cmdprio_bssplit=str[,str] : [io_uring] [libaio]
+       To get a finer control over I/O priority, this option allows
+       specifying the percentage of IOs that must have a priority set
+       depending on the block size of the IO. This option is useful only
+       when used together with the :option:`bssplit` option, that is,
+       multiple different block sizes are used for reads and writes.
+       The format for this option is the same as the format of the
+       :option:`bssplit` option, with the exception that values for
+       trim IOs are ignored. This option is mutually exclusive with the
+       :option:`cmdprio_percentage` option.

 
 .. option:: fixedbufs : [io_uring]
 
 
 .. option:: fixedbufs : [io_uring]
 


@@ -2600,7 +2635,7 @@ with the caveat that when used on the command line, they must come after the
 
        Specify the time between the SIGTERM and SIGKILL signals. Default is 1 second.
 
 
        Specify the time between the SIGTERM and SIGKILL signals. Default is 1 second.
 

-.. option:: std_redirect=boot : [exec]
+.. option:: std_redirect=bool : [exec]

 
        If set, stdout and stderr streams are redirected to files named from the job name. Default is true.
 
 
        If set, stdout and stderr streams are redirected to files named from the job name. Default is true.
 


@@ -2710,7 +2745,7 @@ I/O rate
        Stall the job for the specified period of time after an I/O has completed before issuing the
        next. May be used to simulate processing being done by an application.
        When the unit is omitted, the value is interpreted in microseconds.  See
        Stall the job for the specified period of time after an I/O has completed before issuing the
        next. May be used to simulate processing being done by an application.
        When the unit is omitted, the value is interpreted in microseconds.  See

-       :option:`thinktime_blocks` and :option:`thinktime_spin`.
+       :option:`thinktime_blocks`, :option:`thinktime_iotime` and :option:`thinktime_spin`.

 
 .. option:: thinktime_spin=time
 
 
 .. option:: thinktime_spin=time
 


@@ -2735,6 +2770,18 @@ I/O rate
        :option:`thinktime_blocks` blocks. If this is set to `issue`, then the trigger happens
        at the issue side.
 
        :option:`thinktime_blocks` blocks. If this is set to `issue`, then the trigger happens
        at the issue side.
 

+.. option:: thinktime_iotime=time
+
+       Only valid if :option:`thinktime` is set - control :option:`thinktime`
+       interval by time. The :option:`thinktime` stall is repeated after IOs
+       are executed for :option:`thinktime_iotime`. For example,
+       ``--thinktime_iotime=9s --thinktime=1s`` repeat 10-second cycle with IOs
+       for 9 seconds and stall for 1 second. When the unit is omitted,
+       :option:`thinktime_iotime` is interpreted as a number of seconds. If
+       this option is used together with :option:`thinktime_blocks`, the
+       :option:`thinktime` stall is repeated after :option:`thinktime_iotime`
+       or after :option:`thinktime_blocks` IOs, whichever happens first.
+

 .. option:: rate=int[,int][,int]
 
        Cap the bandwidth used by this job. The number is in bytes/sec, the normal
 .. option:: rate=int[,int][,int]
 
        Cap the bandwidth used by this job. The number is in bytes/sec, the normal


@@ -2974,14 +3021,14 @@ Threads, processes and job synchronization
        between 0 and 7, with 0 being the highest.  See man
        :manpage:`ionice(1)`. Refer to an appropriate manpage for other operating
        systems since meaning of priority may differ. For per-command priority
        between 0 and 7, with 0 being the highest.  See man
        :manpage:`ionice(1)`. Refer to an appropriate manpage for other operating
        systems since meaning of priority may differ. For per-command priority

-       setting, see I/O engine specific `cmdprio_percentage` and `hipri_percentage`
-       options.
+       setting, see I/O engine specific :option:`cmdprio_percentage` and
+       :option:`cmdprio` options.

 
 .. option:: prioclass=int
 
        Set the I/O priority class. See man :manpage:`ionice(1)`. For per-command
 
 .. option:: prioclass=int
 
        Set the I/O priority class. See man :manpage:`ionice(1)`. For per-command

-       priority setting, see I/O engine specific `cmdprio_percentage` and
-       `hipri_percentage` options.
+       priority setting, see I/O engine specific :option:`cmdprio_percentage`
+       and :option:`cmdprio_class` options.

 
 .. option:: cpus_allowed=str
 
 
 .. option:: cpus_allowed=str