Parse options only, don't start any I/O.
+.. option:: --merge-blktrace-only
+
+ Merge blktraces only, don't start any I/O.
+
.. option:: --output=filename
Write output to file `filename`.
Force a full status dump of cumulative (from job start) values at `time`
intervals. This option does *not* provide per-period measurements. So
values such as bandwidth are running averages. When the time unit is omitted,
- `time` is interpreted in seconds.
+ `time` is interpreted in seconds. Note that using this option with
+ ``--output-format=json`` will yield output that technically isn't valid
+ json, since the output will be collated sets of valid json. It will need
+ to be split into valid sets of json after the run.
.. option:: --section=name
bandwidth and IOPS numbers fio only reads beyond the write pointer if
explicitly told to do so. Default: false.
+.. 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 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.
+
+.. option:: zone_reset_threshold=float
+
+ 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.
+
+.. option:: zone_reset_frequency=float
+
+ A number between zero and one that indicates how often a zone reset
+ should be issued if the zone reset threshold has been exceeded. A zone
+ reset is submitted after each (1 / zone_reset_frequency) write
+ requests. This and the previous parameter can be used to simulate
+ garbage collection activity.
+
I/O type
~~~~~~~~
**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
will be read at once. If selected true, input from iolog will be read
gradually. Useful when iolog is very large, or it is generated.
+.. option:: merge_blktrace_file=str
+
+ When specified, rather than replaying the logs passed to :option:`read_iolog`,
+ the logs go through a merge phase which aggregates them into a single
+ blktrace. The resulting file is then passed on as the :option:`read_iolog`
+ parameter. The intention here is to make the order of events consistent.
+ This limits the influence of the scheduler compared to replaying multiple
+ blktraces via concurrent jobs.
+
+.. option:: merge_blktrace_scalars=float_list
+
+ This is a percentage based option that is index paired with the list of
+ files passed to :option:`read_iolog`. When merging is performed, scale
+ the time of each event by the corresponding amount. For example,
+ ``--merge_blktrace_scalars="50:100"`` runs the first trace in halftime
+ and the second trace in realtime. This knob is separately tunable from
+ :option:`replay_time_scale` which scales the trace during runtime and
+ does not change the output of the merge unlike this option.
+
+.. option:: merge_blktrace_iters=float_list
+
+ This is a whole number option that is index paired with the list of files
+ passed to :option:`read_iolog`. When merging is performed, run each trace
+ for the specified number of iterations. For example,
+ ``--merge_blktrace_iters="2:1"`` runs the first trace for two iterations
+ and the second trace for one iteration.
+
.. option:: replay_no_stall=bool
When replaying I/O with :option:`read_iolog` the default behavior is to
.. 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
------------
**trim**
Trim the given file from the given `offset` for `length` bytes.
+
+I/O Replay - Merging Traces
+---------------------------
+
+Colocation is a common practice used to get the most out of a machine.
+Knowing which workloads play nicely with each other and which ones don't is
+a much harder task. While fio can replay workloads concurrently via multiple
+jobs, it leaves some variability up to the scheduler making results harder to
+reproduce. Merging is a way to make the order of events consistent.
+
+Merging is integrated into I/O replay and done when a
+:option:`merge_blktrace_file` is specified. The list of files passed to
+:option:`read_iolog` go through the merge process and output a single file
+stored to the specified file. The output file is passed on as if it were the
+only file passed to :option:`read_iolog`. An example would look like::
+
+ $ 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`.
+
+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
+separated list of percentage scalars. It is index paired with the files passed
+to :option:`read_iolog`.
+
+With scaling, it may be desirable to match the running time of all traces.
+This can be done with :option:`merge_blktrace_iters`. It is index paired with
+:option:`read_iolog` just like :option:`merge_blktrace_scalars`.
+
+In an example, given two traces, A and B, each 60s long. If we want to see
+the impact of trace A issuing IOs twice as fast and repeat trace A over the
+runtime of trace B, the following can be done::
+
+ $ fio --read_iolog="<trace_a>:"<trace_b>" --merge_blktrace_file"<output_file>" --merge_blktrace_scalars="50:100" --merge_blktrace_iters="2:1"
+
+This runs trace A at 2x the speed twice for approximately the same runtime as
+a single run of trace B.
+
+
CPU idleness profiling
----------------------
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.
projects / fio.git / blobdiff