.. option:: max_open_zones=int
- When running a random write test across an entire drive many more
- zones will be open than in a typical application workload. Hence this
- command line option that allows one to limit the number of open zones. The
- number of open zones is defined as the number of zones to which write
- commands are issued.
+ A zone of a zoned block device is in the open state when it is partially
+ written (i.e. not all sectors of the zone have been written). Zoned
+ block devices may have a limit on the total number of zones that can
+ be simultaneously in the open state, that is, the number of zones that
+ can be written to simultaneously. The :option:`max_open_zones` parameter
+ limits the number of zones to which write commands are issued by all fio
+ jobs, that is, limits the number of zones that will be in the open
+ state. This parameter is relevant only if the :option:`zonemode` =zbd is
+ used. The default value is always equal to maximum number of open zones
+ of the target zoned block device and a value higher than this limit
+ cannot be specified by users unless the option
+ :option:`ignore_zone_limits` is specified. When
+ :option:`ignore_zone_limits` is specified or the target device has no
+ limit on the number of zones that can be in an open state,
+ :option:`max_open_zones` can specify 0 to disable any limit on the
+ number of zones that can be simultaneously written to by all jobs.
.. option:: job_max_open_zones=int
- Limit on the number of simultaneously opened zones per single
- thread/process.
+ In the same manner as :option:`max_open_zones`, limit the number of open
+ zones per fio job, that is, the number of zones that a single job can
+ simultaneously write to. A value of zero indicates no limit.
+ Default: zero.
.. option:: ignore_zone_limits=bool
:option:`libblkio_driver`. If
:option:`mem`/:option:`iomem` is not specified, memory
allocation is delegated to libblkio (and so is
- guaranteed to work with the selected *driver*).
+ guaranteed to work with the selected *driver*). One
+ libblkio instance is used per process, so all jobs
+ setting option :option:`thread` will share a single
+ instance (with one queue per thread) and must specify
+ compatible options. Note that some drivers don't allow
+ several instances to access the same device or file
+ simultaneously, but allow it for threads.
I/O engine specific parameters
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[libblkio]
Use poll queues. This is incompatible with
- :option:`libblkio_wait_mode=eventfd <libblkio_wait_mode>`.
+ :option:`libblkio_wait_mode=eventfd <libblkio_wait_mode>` and
+ :option:`libblkio_force_enable_completion_eventfd`.
[pvsync2]
**posix**
Use the posix asynchronous I/O interface to perform one or
more I/O operations asynchronously.
+ **vfio**
+ Use the user-space VFIO-based backend, implemented using
+ libvfn instead of SPDK.
**nil**
Do not transfer any data; just pretend to. This is mainly used
for introspective performance evaluation.
.. option:: xnvme_dev_nsid=int : [xnvme]
- xnvme namespace identifier for userspace NVMe driver, such as SPDK.
+ xnvme namespace identifier for userspace NVMe driver, SPDK or vfio.
+
+.. option:: xnvme_dev_subnqn=str : [xnvme]
+
+ Sets the subsystem NQN for fabrics. This is for xNVMe to utilize a
+ fabrics target with multiple systems.
.. option:: xnvme_iovec=int : [xnvme]
libblkio version in use and are listed at
https://libblkio.gitlab.io/libblkio/blkio.html#drivers
+.. option:: libblkio_path=str : [libblkio]
+
+ Sets the value of the driver-specific "path" property before connecting
+ the libblkio instance, which identifies the target device or file on
+ which to perform I/O. Its exact semantics are driver-dependent and not
+ all drivers may support it; see
+ https://libblkio.gitlab.io/libblkio/blkio.html#drivers
+
.. option:: libblkio_pre_connect_props=str : [libblkio]
- A colon-separated list of libblkio properties to be set after creating
- but before connecting the libblkio instance. Each property must have the
- format ``<name>=<value>``. Colons can be escaped as ``\:``. These are
- set after the engine sets any other properties, so those can be
- overriden. Available properties depend on the libblkio version in use
+ A colon-separated list of additional libblkio properties to be set after
+ creating but before connecting the libblkio instance. Each property must
+ have the format ``<name>=<value>``. Colons can be escaped as ``\:``.
+ These are set after the engine sets any other properties, so those can
+ be overriden. Available properties depend on the libblkio version in use
and are listed at
https://libblkio.gitlab.io/libblkio/blkio.html#properties
+.. option:: libblkio_num_entries=int : [libblkio]
+
+ Sets the value of the driver-specific "num-entries" property before
+ starting the libblkio instance. Its exact semantics are driver-dependent
+ and not all drivers may support it; see
+ https://libblkio.gitlab.io/libblkio/blkio.html#drivers
+
+.. option:: libblkio_queue_size=int : [libblkio]
+
+ Sets the value of the driver-specific "queue-size" property before
+ starting the libblkio instance. Its exact semantics are driver-dependent
+ and not all drivers may support it; see
+ https://libblkio.gitlab.io/libblkio/blkio.html#drivers
+
.. option:: libblkio_pre_start_props=str : [libblkio]
- A colon-separated list of libblkio properties to be set after connecting
- but before starting the libblkio instance. Each property must have the
- format ``<name>=<value>``. Colons can be escaped as ``\:``. These are
- set after the engine sets any other properties, so those can be
- overriden. Available properties depend on the libblkio version in use
+ A colon-separated list of additional libblkio properties to be set after
+ connecting but before starting the libblkio instance. Each property must
+ have the format ``<name>=<value>``. Colons can be escaped as ``\:``.
+ These are set after the engine sets any other properties, so those can
+ be overriden. Available properties depend on the libblkio version in use
and are listed at
https://libblkio.gitlab.io/libblkio/blkio.html#properties
**loop**
Use a busy loop with a non-blocking call to ``blkioq_do_io()``.
+.. option:: libblkio_force_enable_completion_eventfd : [libblkio]
+
+ Enable the queue's completion eventfd even when unused. This may impact
+ performance. The default is to enable it only if
+ :option:`libblkio_wait_mode=eventfd <libblkio_wait_mode>`.
+
I/O depth
~~~~~~~~~
projects / fio.git / blobdiff