**pvsync2**
Basic :manpage:`preadv2(2)` or :manpage:`pwritev2(2)` I/O.
+ **io_uring**
+ Fast Linux native asynchronous I/O. Supports async IO
+ for both direct and buffered IO.
+ This engine defines engine specific options.
+
**libaio**
Linux native asynchronous I/O. Note that Linux may only support
queued behavior with non-buffered I/O (set ``direct=1`` or
Asynchronous read and write using DDN's Infinite Memory Engine (IME).
This engine will try to stack as much IOs as possible by creating
requests for IME. FIO will then decide when to commit these requests.
+ **libiscsi**
+ Read and write iscsi lun with libiscsi.
+ **nbd**
+ Read and write a Network Block Device (NBD).
I/O engine specific parameters
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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]
+
+ 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:: 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.
+
+.. option:: sqthread_poll : [io_uring]
+
+ Normally fio will submit IO by issuing a system call to notify the
+ kernel of available items in the SQ ring. If this option is set, the
+ act of submitting IO will be done by a polling thread in the kernel.
+ This frees up cycles for fio, at the cost of using more CPU in the
+ system.
+
+.. option:: sqthread_poll_cpu : [io_uring]
+
+ When :option:`sqthread_poll` is set, this option provides a way to
+ define which CPU should be used for the polling thread.
+
.. option:: userspace_reap : [libaio]
Normally, with the libaio engine in use, fio will use the
turns on verbose logging from libcurl, 2 additionally enables
HTTP IO tracing. Default is **0**
+.. option:: uri=str : [nbd]
+
+ Specify the NBD URI of the server to test. The string
+ is a standard NBD URI
+ (see https://github.com/NetworkBlockDevice/nbd/tree/master/doc).
+ Example URIs: nbd://localhost:10809
+ nbd+unix:///?socket=/tmp/socket
+ nbds://tlshost/exportname
+
I/O depth
~~~~~~~~~
``serialize_overlap`` tells fio to avoid provoking this behavior by explicitly
serializing in-flight I/Os that have a non-zero overlap. Note that setting
this option can reduce both performance and the :option:`iodepth` achieved.
- Additionally this option does not work when :option:`io_submit_mode` is set to
- offload. Default: false.
+
+ This option only applies to I/Os issued for a single job except when it is
+ enabled along with :option:`io_submit_mode`=offload. In offload mode, fio
+ will check for overlap among all I/Os submitted by offload jobs with :option:`serialize_overlap`
+ enabled.
+
+ Default: false.
.. option:: io_submit_mode=str
.. option:: replay_align=int
- Force alignment of I/O offsets and lengths in a trace to this power of 2
- value.
+ Force alignment of the byte offsets in a trace to this value. The value
+ must be a power of 2.
.. option:: replay_scale=int
- Scale sector offsets down by this factor when replaying traces.
+ Scale byte offsets down by this factor when replaying traces. Should most
+ likely use :option:`replay_align` as well.
.. option:: replay_skip=str
data from the rolling collection window. Threshold limits can be expressed
as a fixed value or as a percentage of the mean in the collection window.
+ When using this feature, most jobs should include the :option:`time_based`
+ and :option:`runtime` options or the :option:`loops` option so that fio does not
+ stop running after it has covered the full size of the specified file(s) or device(s).
+
**iops**
Collect IOPS data. Stop the job if all individual IOPS measurements
are within the specified limit of the mean IOPS (e.g., ``iops:2``
2;card0;0;0;7139336;121836;60004;1;10109;27.932460;116.933948;220;126861;3495.446807;1085.368601;226;126864;3523.635629;1089.012448;24063;99944;50.275485%;59818.274627;5540.657370;7155060;122104;60004;1;8338;29.086342;117.839068;388;128077;5032.488518;1234.785715;391;128085;5061.839412;1236.909129;23436;100928;50.287926%;59964.832030;5644.844189;14.595833%;19.394167%;123706;0;7313;0.1%;0.1%;0.1%;0.1%;0.1%;0.1%;100.0%;0.00%;0.00%;0.00%;0.00%;0.00%;0.00%;0.01%;0.02%;0.05%;0.16%;6.04%;40.40%;52.68%;0.64%;0.01%;0.00%;0.01%;0.00%;0.00%;0.00%;0.00%;0.00%
A description of this job goes here.
-The job description (if provided) follows on a second line.
+The job description (if provided) follows on a second line for terse v2.
+It appears on the same line for other terse versions.
To enable terse output, use the :option:`--minimal` or
:option:`--output-format`\=terse command line options. The
terse_version_3;fio_version;jobname;groupid;error;read_kb;read_bandwidth;read_iops;read_runtime_ms;read_slat_min;read_slat_max;read_slat_mean;read_slat_dev;read_clat_min;read_clat_max;read_clat_mean;read_clat_dev;read_clat_pct01;read_clat_pct02;read_clat_pct03;read_clat_pct04;read_clat_pct05;read_clat_pct06;read_clat_pct07;read_clat_pct08;read_clat_pct09;read_clat_pct10;read_clat_pct11;read_clat_pct12;read_clat_pct13;read_clat_pct14;read_clat_pct15;read_clat_pct16;read_clat_pct17;read_clat_pct18;read_clat_pct19;read_clat_pct20;read_tlat_min;read_lat_max;read_lat_mean;read_lat_dev;read_bw_min;read_bw_max;read_bw_agg_pct;read_bw_mean;read_bw_dev;write_kb;write_bandwidth;write_iops;write_runtime_ms;write_slat_min;write_slat_max;write_slat_mean;write_slat_dev;write_clat_min;write_clat_max;write_clat_mean;write_clat_dev;write_clat_pct01;write_clat_pct02;write_clat_pct03;write_clat_pct04;write_clat_pct05;write_clat_pct06;write_clat_pct07;write_clat_pct08;write_clat_pct09;write_clat_pct10;write_clat_pct11;write_clat_pct12;write_clat_pct13;write_clat_pct14;write_clat_pct15;write_clat_pct16;write_clat_pct17;write_clat_pct18;write_clat_pct19;write_clat_pct20;write_tlat_min;write_lat_max;write_lat_mean;write_lat_dev;write_bw_min;write_bw_max;write_bw_agg_pct;write_bw_mean;write_bw_dev;cpu_user;cpu_sys;cpu_csw;cpu_mjf;cpu_minf;iodepth_1;iodepth_2;iodepth_4;iodepth_8;iodepth_16;iodepth_32;iodepth_64;lat_2us;lat_4us;lat_10us;lat_20us;lat_50us;lat_100us;lat_250us;lat_500us;lat_750us;lat_1000us;lat_2ms;lat_4ms;lat_10ms;lat_20ms;lat_50ms;lat_100ms;lat_250ms;lat_500ms;lat_750ms;lat_1000ms;lat_2000ms;lat_over_2000ms;disk_name;disk_read_iops;disk_write_iops;disk_read_merges;disk_write_merges;disk_read_ticks;write_ticks;disk_queue_time;disk_util
+In client/server mode terse output differs from what appears when jobs are run
+locally. Disk utilization data is omitted from the standard terse output and
+for v3 and later appears on its own separate line at the end of each terse
+reporting cycle.
+
JSON output
------------
its values in a separate row. Further, when using windowed logging the *block
size* and *offset* entries will always contain 0.
+
Client/Server
-------------
/mnt/nfs/fio/192.168.10.120.fileio.tmp
/mnt/nfs/fio/192.168.10.121.fileio.tmp
+
+Terse output in client/server mode will differ slightly from what is produced
+when fio is run in stand-alone mode. See the terse output section for details.