so. Default: false.
.TP
.BI max_open_zones \fR=\fPint
-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 by all
-threads/processes.
+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 limit a 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 \fBmax_open_zones\fR 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
+\fBzonemode=zbd\fR 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 \fBignore_zone_limits\fR is
+specified. When \fBignore_zone_limits\fR is specified or the target device has
+no limit on the number of zones that can be in an open state,
+\fBmax_open_zones\fR can specify 0 to disable any limit on the number of zones
+that can be simultaneously written to by all jobs.
.TP
.BI job_max_open_zones \fR=\fPint
-Limit on the number of simultaneously opened zones per single thread/process.
+In the same manner as \fBmax_open_zones\fR, 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.
.TP
.BI ignore_zone_limits \fR=\fPbool
If this option is used, fio will ignore the maximum number of open zones limit
value to be larger than the device reported limit. Default: false.
.TP
.BI zone_reset_threshold \fR=\fPfloat
-A number between zero and one that indicates the ratio of logical blocks with
-data to the total number of logical blocks in the test above which zones
-should be reset periodically.
+A number between zero and one that indicates the ratio of written bytes in the
+zones with write pointers in the IO range to the size of the IO range. When
+current ratio is above this ratio, zones are reset periodically as
+\fBzone_reset_frequency\fR specifies. If there are multiple jobs when using this
+option, the IO range for all write jobs has to be the same.
.TP
.BI zone_reset_frequency \fR=\fPfloat
A number between zero and one that indicates how often a zone reset should be
OpenBSD and ZFS on Solaris don't support direct I/O. On Windows the synchronous
ioengines don't support direct I/O. Default: false.
.TP
-.BI atomic \fR=\fPbool
-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.
-.TP
.BI buffered \fR=\fPbool
If value is true, use buffered I/O. This is the opposite of the
\fBdirect\fR option. Defaults to true.
.P
\fBsequential\fR is only useful for random I/O, where fio would normally
generate a new random offset for every I/O. If you append e.g. 8 to randread,
-you would get a new random offset for every 8 I/Os. The result would be a
-seek for only every 8 I/Os, instead of for every I/O. Use `rw=randread:8'
-to specify that. As sequential I/O is already sequential, setting
-\fBsequential\fR for that would not result in any differences. \fBidentical\fR
-behaves in a similar fashion, except it sends the same offset 8 number of
-times before generating a new offset.
+i.e. `rw=randread:8' you would get a new random offset for every 8 I/Os. The
+result would be a sequence of 8 sequential offsets with a random starting
+point. However this behavior may change if a sequential I/O reaches end of the
+file. As sequential I/O is already sequential, setting \fBsequential\fR for
+that would not result in any difference. \fBidentical\fR behaves in a similar
+fashion, except it sends the same offset 8 number of times before generating a
+new offset.
+.P
+.P
+Example #1:
+.RS
+.P
+.PD 0
+rw=randread:8
+.P
+rw_sequencer=sequential
+.P
+bs=4k
+.PD
+.RE
+.P
+The generated sequence of offsets will look like this:
+4k, 8k, 12k, 16k, 20k, 24k, 28k, 32k, 92k, 96k, 100k, 104k, 108k, 112k, 116k,
+120k, 48k, 52k ...
+.P
+.P
+Example #2:
+.RS
+.P
+.PD 0
+rw=randread:8
+.P
+rw_sequencer=identical
+.P
+bs=4k
+.PD
+.RE
+.P
+The generated sequence of offsets will look like this:
+4k, 4k, 4k, 4k, 4k, 4k, 4k, 4k, 92k, 92k, 92k, 92k, 92k, 92k, 92k, 92k, 48k,
+48k, 48k ...
.RE
.TP
.BI unified_rw_reporting \fR=\fPstr
before overwriting. The \fBtrimwrite\fR mode works well for this
constraint.
.TP
-.B 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.
-.TP
.B dev\-dax
Read and write using device DAX to a persistent memory device (e.g.,
/dev/dax0.0) through the PMDK libpmem library.
Use the posix asynchronous I/O interface to perform one or more I/O operations
asynchronously.
.TP
+.BI vfio
+Use the user-space VFIO-based backend, implemented using libvfn instead of
+SPDK.
+.TP
.BI nil
Do not transfer any data; just pretend to. This is mainly used for
introspective performance evaluation.
.RE
.TP
.BI (xnvme)xnvme_dev_nsid\fR=\fPint
-xnvme namespace identifier for userspace NVMe driver such as SPDK.
+xnvme namespace identifier for userspace NVMe driver SPDK or vfio.
+.TP
+.BI (xnvme)xnvme_dev_subnqn\fR=\fPstr
+Sets the subsystem NQN for fabrics. This is for xNVMe to utilize a fabrics
+target with multiple systems.
+.TP
+.BI (xnvme)xnvme_mem\fR=\fPstr
+Select the xnvme memory backend. This can take these values.
+.RS
+.RS
+.TP
+.B posix
+This is the default posix memory backend for linux NVMe driver.
+.TP
+.BI hugepage
+Use hugepages, instead of existing posix memory backend. The memory backend
+uses hugetlbfs. This require users to allocate hugepages, mount hugetlbfs and
+set an enviornment variable for XNVME_HUGETLB_PATH.
+.TP
+.BI spdk
+Uses SPDK's memory allocator.
+.TP
+.BI vfio
+Uses libvfn's memory allocator. This also specifies the use of libvfn backend
+instead of SPDK.
+.RE
+.RE
.TP
.BI (xnvme)xnvme_iovec
If this option is set, xnvme will use vectored read/write commands.
projects / fio.git / blobdiff