X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=e7142c57b03df0e6f500b35ad95cf712d4c20617;hb=b6e71b39c8fbdb2c48d4f60d373ba802f07c37cf;hp=2a70b7c629b6d6470625ac98e02dad555571f1ed;hpb=07dff7d1d614b33e3a6d3e3ade38ce648b53a632;p=fio.git diff --git a/HOWTO b/HOWTO index 2a70b7c6..e7142c57 100644 --- a/HOWTO +++ b/HOWTO @@ -182,8 +182,10 @@ Command line options .. option:: --status-interval=time - Force full status dump every `time` period passed. When the unit is - omitted, the value is interpreted in seconds. + 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. .. option:: --section=name @@ -215,6 +217,9 @@ Command line options .. option:: --max-jobs=nr Set the maximum number of threads/processes to support to `nr`. + NOTE: On Linux, it may be necessary to increase the shared-memory + limit (:file:`/proc/sys/kernel/shmmax`) if fio runs into errors while + creating jobs. .. option:: --server=args @@ -228,7 +233,7 @@ Command line options .. option:: --client=hostname Instead of running the jobs locally, send and run them on the given `hostname` - or set of `hostname`s. See `Client/Server`_ section. + or set of `hostname`\s. See `Client/Server`_ section. .. option:: --remote-config=file @@ -790,6 +795,13 @@ Target file/device named :file:`testfiles.4`. The default of :file:`$jobname.$jobnum.$filenum` will be used if no other format specifier is given. + If you specify a path then the directories will be created up to the + main directory for the file. So for example if you specify + ``filename_format=a/b/c/$jobnum`` then the directories a/b/c will be + created before the file setup part of the job. If you specify + :option:`directory` then the path will be relative that directory, + otherwise it is treated as the absolute path. + .. option:: unique_filename=bool To avoid collisions between networked clients, fio defaults to prefixing any @@ -1116,13 +1128,20 @@ I/O type .. option:: offset=int Start I/O at the provided offset in the file, given as either a fixed size in - bytes or a percentage. If a percentage is given, the next ``blockalign``-ed - offset will be used. Data before the given offset will not be touched. This + bytes or a percentage. If a percentage is given, the generated offset will be + aligned to the minimum ``blocksize`` or to the value of ``offset_align`` if + provided. Data before the given offset will not be touched. This effectively caps the file size at `real_size - offset`. Can be combined with :option:`size` to constrain the start and end range of the I/O workload. A percentage can be specified by a number between 1 and 100 followed by '%', for example, ``offset=20%`` to specify 20%. +.. option:: offset_align=int + + If set to non-zero value, the byte offset generated by a percentage ``offset`` + is aligned upwards to this value. Defaults to 0 meaning that a percentage + offset is aligned to the minimum block size. + .. option:: offset_increment=int If this is provided, then the real offset becomes `offset + offset_increment @@ -1703,7 +1722,7 @@ I/O engine Doesn't transfer any data, but burns CPU cycles according to the :option:`cpuload` and :option:`cpuchunks` options. Setting :option:`cpuload`\=85 will cause that job to do nothing but burn 85% - of the CPU. In case of SMP machines, use :option:`numjobs`= + of the CPU. In case of SMP machines, use :option:`numjobs`\= to get desired CPU usage, as the cpuload only loads a single CPU at the desired rate. A job never finishes unless there is at least one non-cpuio job. @@ -1795,6 +1814,10 @@ I/O engine absolute or relative. See :file:`engines/skeleton_external.c` for details of writing an external I/O engine. + **filecreate** + Simply create the files and do no IO to them. You still need to + set `filesize` so that all the accounting still occurs, but no + actual IO will be done other than creating the file. I/O engine specific parameters ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -2860,7 +2883,15 @@ Measurements and reporting .. option:: clat_percentiles=bool - Enable the reporting of percentiles of completion latencies. + Enable the reporting of percentiles of completion latencies. This + option is mutually exclusive with :option:`lat_percentiles`. + +.. option:: lat_percentiles=bool + + Enable the reporting of percentiles of IO latencies. This is similar + to :option:`clat_percentiles`, except that this includes the + submission latency. This option is mutually exclusive with + :option:`clat_percentiles`. .. option:: percentile_list=float_list @@ -3381,6 +3412,15 @@ minimal output v3, separated by semicolons:: 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 +JSON output +------------ + +The `json` output format is intended to be both human readable and convenient +for automated parsing. For the most part its sections mirror those of the +`normal` output. The `runtime` value is reported in msec and the `bw` value is +reported in 1024 bytes per second units. + + JSON+ output ------------