`filename` semantic (which generates a file for each clone if not
specified, but lets all clones use the same file if set).
- See the :option:`filename` option for information on how to escape "``:``" and
- "``\``" characters within the directory path itself.
+ See the :option:`filename` option for information on how to escape "``:``"
+ characters within the directory path itself.
Note: To control the directory fio will use for internal state files
use :option:`--aux-path`.
by this option will be :option:`size` divided by number of files unless an
explicit size is specified by :option:`filesize`.
- 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 :file:`/dev/dsk/foo@3,0:c` then you
would use ``filename=/dev/dsk/foo@3,0\:c`` and if the path is
- :file:`F:\\filename` then you would use ``filename=F\:\\filename``.
+ :file:`F:\\filename` then you would use ``filename=F\:\filename``.
On Windows, disk devices are accessed as :file:`\\\\.\\PhysicalDrive0` for
the first device, :file:`\\\\.\\PhysicalDrive1` for the second etc.
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**.
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
.. 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.
set `filesize` so that all the accounting still occurs, but no
actual I/O will be done other than creating the file.
+ **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.
+
**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
:option:`ioengine` that defines them is selected.
-.. option:: hipri : [io_uring]
+.. option:: cmdprio_percentage=int : [io_uring] [libaio]
- 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.
+ 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.
.. option:: fixedbufs : [io_uring]
- If fio is asked to do direct IO, then Linux will map pages for each
- IO call, and 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.
+ If fio is asked to do direct IO, then Linux will map pages for each
+ IO call, and 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.
+
+.. option:: hipri : [io_uring]
+
+ 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.
.. option:: registerfiles : [io_uring]
+
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 submission and completion part more lightweight. Required
multiple paths exist between the client and the server or in certain loopback
configurations.
+.. option:: lstat=bool : [filestat]
+
+ Use lstat(2) to measure lookup/getattr performance. Default is 0.
+
.. option:: readfua=bool : [sg]
With readfua option set to 1, read operations include
(``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 :option:`filename` option for information on how to
- escape ':' and '\' characters within the file names. These files will
+ escape ':' characters within the file names. These files will
be sequentially assigned to job clones created by :option:`numjobs`.
.. option:: read_iolog_chunked=bool
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
:manpage:`ionice(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.
.. option:: prioclass=int
- Set the I/O priority class. See man :manpage:`ionice(1)`.
+ 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.
.. option:: cpus_allowed=str
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.
.. 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
$ fio --read_iolog="<file1>:<file2>" --merge_blktrace_file="<output_file>"
Creating only the merged file can be done by passing the command line argument
-:option:`merge-blktrace-only`.
+:option:`--merge-blktrace-only`.
Scaling traces can be done to see the relative impact of any particular trace
being slowed down or sped up. :option:`merge_blktrace_scalars` takes in a colon
projects / fio.git / blobdiff