Add example job file for exit_what

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 4fef1504a410a205c95c7c85b489f0068bceb1a5..41a667af4406a17b215952faa7ef3511bc0bb801 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1173,6 +1173,10 @@ I/O type
                        Pre-allocate via :manpage:`fallocate(2)` with
                        FALLOC_FL_KEEP_SIZE set.
 
+               **truncate**
+                       Extend file to final size via :manpage:`ftruncate(2)`
+                       instead of allocating.
+
                **0**
                        Backward-compatible alias for **none**.
 
@@ -1182,7 +1186,15 @@ I/O type
        May not be available on all supported platforms. **keep** is only available
        on Linux. If using ZFS on Solaris this cannot be set to **posix**
        because ZFS doesn't support pre-allocation. Default: **native** if any
-       pre-allocation methods are available, **none** if not.
+       pre-allocation methods except **truncate** are available, **none** if not.
+
+       Note that using **truncate** on Windows will interact surprisingly
+       with non-sequential write patterns. When writing to a file that has
+       been extended by setting the end-of-file information, Windows will
+       backfill the unwritten portion of the file up to that offset with
+       zeroes before issuing the new write. This means that a single small
+       write to the end of an extended file will stall until the entire
+       file has been filled with zeroes.
 
 .. option:: fadvise_hint=str
 
@@ -1279,7 +1291,7 @@ I/O type
 .. option:: fdatasync=int
 
        Like :option:`fsync` but uses :manpage:`fdatasync(2)` to only sync data and
-       not metadata blocks.  In Windows, FreeBSD, and DragonFlyBSD there is no
+       not metadata blocks. In Windows, FreeBSD, DragonFlyBSD or OSX there is no
        :manpage:`fdatasync(2)` so this falls back to using :manpage:`fsync(2)`.
        Defaults to 0, which means fio does not periodically issue and wait for a
        data-only sync to complete.
@@ -2713,7 +2725,7 @@ Threads, processes and job synchronization
                        Each job will get a unique CPU from the CPU set.
 
        **shared** is the default behavior, if the option isn't specified. If
-       **split** is specified, then fio will will assign one cpu per job. If not
+       **split** is specified, then fio will assign one cpu per job. If not
        enough CPUs are given for the jobs listed, then fio will roundrobin the CPUs
        in the set.
 
@@ -2802,9 +2814,21 @@ Threads, processes and job synchronization
 
 .. option:: exitall
 
-       By default, fio will continue running all other jobs when one job finishes
-       but sometimes this is not the desired action.  Setting ``exitall`` will
-       instead make fio terminate all other jobs when one job finishes.
+       By default, fio will continue running all other jobs when one job finishes.
+       Sometimes this is not the desired action.  Setting ``exitall`` will instead
+       make fio terminate all jobs in the same group, as soon as one job of that
+       group finishes.
+
+.. option:: exit_what
+
+       By default, fio will continue running all other jobs when one job finishes.
+       Sometimes this is not the desired action. Setting ``exit_all`` will
+       instead make fio terminate all jobs in the same group. The option
+        ``exit_what`` allows to control which jobs get terminated when ``exitall`` is
+        enabled. The default is ``group`` and does not change the behaviour of
+        ``exitall``. The setting ``all`` terminates all jobs. The setting ``stonewall``
+        terminates all currently running jobs across all groups and continues execution
+        with the next stonewalled group.
 
 .. option:: exec_prerun=str