X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=a1513e1259f7cc3001fb185a662150a9527dba34;hp=16ae708c20dda8bcd2a699249759612a26e64232;hb=645943c03a60a61fc2494480cde1f051f8a14111;hpb=eccce61a4b9863742bbb267690d118d45e309378 diff --git a/HOWTO b/HOWTO index 16ae708c..a1513e12 100644 --- a/HOWTO +++ b/HOWTO @@ -111,9 +111,6 @@ Command line options format. `json+` is like `json`, except it adds a full dump of the latency buckets. -.. option:: --runtime - Limit run time to runtime seconds. - .. option:: --bandwidth-log Generate aggregate bandwidth logs. @@ -185,8 +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 @@ -218,6 +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 ('/proc/sys/kernel/shmmax') if fio runs into errors while + creating jobs. .. option:: --server=args @@ -793,6 +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 @@ -950,7 +959,7 @@ I/O type .. option:: direct=bool If value is true, use non-buffered I/O. This is usually O_DIRECT. Note that - ZFS on Solaris doesn't support direct I/O. On Windows the synchronous + OpenBSD and ZFS on Solaris don't support direct I/O. On Windows the synchronous ioengines don't support direct I/O. Default: false. .. option:: atomic=bool @@ -1794,8 +1803,14 @@ I/O engine **external** Prefix to specify loading an external I/O engine object file. Append the engine filename, e.g. ``ioengine=external:/tmp/foo.o`` to load - ioengine :file:`foo.o` in :file:`/tmp`. + ioengine :file:`foo.o` in :file:`/tmp`. The path can be either + 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -2861,7 +2876,15 @@ 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 @@ -3382,6 +3405,15 @@ 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 ------------ @@ -3584,7 +3616,7 @@ and IOPS. The logs share a common format, which looks like this: on the type of log, it will be one of the following: **Latency log** - Value is latency in usecs + Value is latency in nsecs **Bandwidth log** Value is in KiB/sec **IOPS log**