Merge branch 'trim-support' of https://github.com/ankit-sam/fio

[fio.git] / HOWTO.rst

diff --git a/HOWTO.rst b/HOWTO.rst
index 158c5d897e520c5d075d201cee8b10bf6fc81386..5240f9da866d76da6d044961585d3b6249b3d514 100644 (file)
--- a/HOWTO.rst
+++ b/HOWTO.rst
@@ -686,10 +686,12 @@ Time related parameters
 
 .. option:: runtime=time
 
-       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.
 
 .. option:: time_based
 
@@ -1110,12 +1112,6 @@ I/O type
        OpenBSD and ZFS on Solaris don't support direct I/O.  On Windows the synchronous
        ioengines don't support direct I/O.  Default: false.
 
-.. option:: atomic=bool
-
-       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.
-
 .. option:: buffered=bool
 
        If value is true, use buffered I/O. This is the opposite of the
@@ -2147,11 +2143,6 @@ I/O engine
                        before overwriting. The `trimwrite` mode works well for this
                        constraint.
 
-               **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.
-
                **dev-dax**
                        Read and write using device DAX to a persistent memory device (e.g.,
                        /dev/dax0.0) through the PMDK libpmem library.
@@ -2434,6 +2425,18 @@ with the caveat that when used on the command line, they must come after the
        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.
 
+.. option:: fdp=bool : [io_uring_cmd]
+
+       Enable Flexible Data Placement mode for write commands.
+
+.. option:: fdp_pli=str : [io_uring_cmd]
+
+       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
+        ``fdp_pli=0,2,5``.
+
 .. option:: cpuload=int : [cpuio]
 
        Attempt to use the specified percentage of CPU cycles. This is a mandatory
@@ -3818,10 +3821,11 @@ Steady state
 
 .. option:: steadystate_duration=time, ss_dur=time
 
-       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.
+        A rolling window of this duration will be used to judge whether steady
+        state has been reached. Data will be collected every
+        :option:`ss_interval`.  The default is 0 which disables steady state
+        detection.  When the unit is omitted, the value is interpreted in
+        seconds.
 
 .. option:: steadystate_ramp_time=time, ss_ramp=time
 
@@ -3829,6 +3833,14 @@ Steady state
        collection for checking the steady state job termination criterion. The
        default is 0.  When the unit is omitted, the value is interpreted in seconds.
 
+.. option:: steadystate_check_interval=time, ss_interval=time
+
+        The values during the rolling window will be collected with a period of
+        this value. If :option:`ss_interval` is 30s and :option:`ss_dur` 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.
+
 
 Measurements and reporting
 ~~~~~~~~~~~~~~~~~~~~~~~~~~