:manpage:`read(2)` and :manpage:`write(2)` for asynchronous
I/O. Requires :option:`filename` option to specify either block or
character devices.
+ The sg engine includes engine specific options.
**null**
Doesn't transfer any data, just pretends to. This is mainly used to
**pmemblk**
Read and write using filesystem DAX to a file on a filesystem
- mounted with DAX on a persistent memory device through the NVML
+ 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 NVML libpmem library.
+ /dev/dax0.0) through the PMDK libpmem library.
**external**
Prefix to specify loading an external I/O engine object file. Append
**libpmem**
Read and write using mmap I/O to a file on a filesystem
- mounted with DAX on a persistent memory device through the NVML
+ mounted with DAX on a persistent memory device through the PMDK
libpmem library.
I/O engine specific parameters
multiple paths exist between the client and the server or in certain loopback
configurations.
+.. option:: readfua=bool : [sg]
+
+ With readfua option set to 1, read operations include
+ the force unit access (fua) flag. Default is 0.
+
+.. option:: writefua=bool : [sg]
+
+ With writefua option set to 1, write operations include
+ the force unit access (fua) flag. Default is 0.
+
+
I/O depth
~~~~~~~~~
still respecting ordering. The result is the same I/O pattern to a given
device, but different timings.
+.. option:: replay_time_scale=int
+
+ When replaying I/O with :option:`read_iolog`, fio will honor the
+ original timing in the trace. With this option, it's possible to scale
+ the time. It's a percentage option, if set to 50 it means run at 50%
+ the original IO rate in the trace. If set to 200, run at twice the
+ original IO rate. Defaults to 100.
+
.. option:: replay_redirect=str
While replaying I/O patterns using :option:`read_iolog` the default behavior
Scale sector offsets down by this factor when replaying traces.
+.. option:: replay_skip=str
+
+ Sometimes it's useful to skip certain IO types in a replay trace.
+ This could be, for instance, eliminating the writes in the trace.
+ Or not replaying the trims/discards, if you are redirecting to
+ a device that doesn't support them. This option takes a comma
+ separated list of read, write, trim, sync.
+
Threads, processes and job synchronization
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Set the I/O priority class. See man :manpage:`ionice(1)`.
-.. option:: cpumask=int
-
- Set the CPU affinity of this job. The parameter given is a bit mask of
- allowed CPUs the job may run on. So if you want the allowed CPUs to be 1
- and 5, you would pass the decimal value of (1 << 1 | 1 << 5), or 34. See man
- :manpage:`sched_setaffinity(2)`. This may not work on all supported
- operating systems or kernel versions. This option doesn't work well for a
- higher CPU count than what you can store in an integer mask, so it can only
- control cpus 1-32. For boxes with larger CPU counts, use
- :option:`cpus_allowed`.
-
.. option:: cpus_allowed=str
Controls the same options as :option:`cpumask`, but accepts a textual
- specification of the permitted CPUs instead. So to use CPUs 1 and 5 you
- would specify ``cpus_allowed=1,5``. This option also allows a range of CPUs
- to be specified -- say you wanted a binding to CPUs 1, 5, and 8 to 15, you
- would set ``cpus_allowed=1,5,8-15``.
+ specification of the permitted CPUs instead and CPUs are indexed from 0. So
+ to use CPUs 0 and 5 you would specify ``cpus_allowed=0,5``. This option also
+ allows a range of CPUs to be specified -- say you wanted a binding to CPUs
+ 0, 5, and 8 to 15, you would set ``cpus_allowed=0,5,8-15``.
+
+ On Windows, when ``cpus_allowed`` is unset only CPUs from fio's current
+ processor group will be used and affinity settings are inherited from the
+ system. An fio build configured to target Windows 7 makes options that set
+ CPUs processor group aware and values will set both the processor group
+ and a CPU from within that group. For example, on a system where processor
+ group 0 has 40 CPUs and processor group 1 has 32 CPUs, ``cpus_allowed``
+ values between 0 and 39 will bind CPUs from processor group 0 and
+ ``cpus_allowed`` values between 40 and 71 will bind CPUs from processor
+ group 1. When using ``cpus_allowed_policy=shared`` all CPUs specified by a
+ single ``cpus_allowed`` option must be from the same processor group. For
+ Windows fio builds not built for Windows 7, CPUs will only be selected from
+ (and be relative to) whatever processor group fio happens to be running in
+ and CPUs from other processor groups cannot be used.
.. option:: cpus_allowed_policy=str
enough CPUs are given for the jobs listed, then fio will roundrobin the CPUs
in the set.
+.. option:: cpumask=int
+
+ Set the CPU affinity of this job. The parameter given is a bit mask of
+ allowed CPUs the job may run on. So if you want the allowed CPUs to be 1
+ and 5, you would pass the decimal value of (1 << 1 | 1 << 5), or 34. See man
+ :manpage:`sched_setaffinity(2)`. This may not work on all supported
+ operating systems or kernel versions. This option doesn't work well for a
+ higher CPU count than what you can store in an integer mask, so it can only
+ control cpus 1-32. For boxes with larger CPU counts, use
+ :option:`cpus_allowed`.
+
.. option:: numa_cpu_nodes=str
Set this job running on specified NUMA nodes' CPUs. The arguments allow
previously written file. If the data direction includes any form of write,
the verify will be of the newly written data.
-.. option:: verifysort=bool
-
- If true, fio will sort written verify blocks when it deems it faster to read
- them back in a sorted manner. This is often the case when overwriting an
- existing file, since the blocks are already laid out in the file system. You
- can ignore this option unless doing huge amounts of really fast I/O where
- the red-black tree sorting CPU time becomes significant. Default: true.
-
-.. option:: verifysort_nr=int
-
- Pre-load and sort verify blocks for a read workload.
-
.. option:: verify_offset=int
Swap the verification header with data somewhere else in the block before
Define the set of CPUs that are allowed to handle online log compression for
the I/O jobs. This can provide better isolation between performance
- sensitive jobs, and background compression work.
+ sensitive jobs, and background compression work. See
+ :option:`cpus_allowed` for the format used.
.. option:: log_store_compressed=bool
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