Fio defaults to read if the option is not specified.
For mixed I/O, the default split is 50/50. For certain types of io the result
may still be skewed a bit, since the speed may be different. It is possible to
-specify a number of IO's to do before getting a new offset, this is done by
+specify a number of IOs to do before getting a new offset, this is done by
appending a `:\fI<nr>\fR to the end of the string given. For a random read, it
would look like \fBrw=randread:8\fR for passing in an offset modifier with a
value of 8. If the postfix is used with a sequential IO pattern, then the value
.P
\fBsequential\fR is only useful for random IO, where fio would normally
generate a new random offset for every IO. If you append eg 8 to randread, you
-would get a new random offset for every 8 IO's. The result would be a seek for
-only every 8 IO's, instead of for every IO. Use \fBrw=randread:8\fR to specify
+would get a new random offset for every 8 IOs. The result would be a seek for
+only every 8 IOs, instead of for every IO. Use \fBrw=randread:8\fR to specify
that. As sequential IO 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
Set RWF_HIPRI on IO, indicating to the kernel that it's of
higher priority than normal.
.TP
+.BI (pvsync2)hipri_percentage
+When hipri is set this determines the probability of a pvsync2 IO being high
+priority. The default is 100%.
+.TP
.BI (net,netsplice)hostname \fR=\fPstr
The host name or IP address to use for TCP or UDP based IO.
If the job is a TCP listener or UDP reader, the hostname is not
Number of I/Os performed by all groups.
.TP
.B merge
-Number of merges in the I/O scheduler.
+Number of merges performed by the I/O scheduler.
.TP
.B ticks
Number of ticks we kept the disk busy.
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_max;read_clat_min;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_max;write_clat_min;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;pu_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
.fi
.RE
+.SH JSON+ OUTPUT
+The \fBjson+\fR output format is identical to the \fBjson\fR output format except that it
+adds a full dump of the completion latency bins. Each \fBbins\fR object contains a
+set of (key, value) pairs where keys are latency durations and values count how
+many I/Os had completion latencies of the corresponding duration. For example,
+consider:
+
+.RS
+"bins" : { "87552" : 1, "89600" : 1, "94720" : 1, "96768" : 1, "97792" : 1, "99840" : 1, "100864" : 2, "103936" : 6, "104960" : 534, "105984" : 5995, "107008" : 7529, ... }
+.RE
+
+This data indicates that one I/O required 87,552ns to complete, two I/Os required
+100,864ns to complete, and 7529 I/Os required 107,008ns to complete.
+
+Also included with fio is a Python script \fBfio_jsonplus_clat2csv\fR that takes
+json+ output and generates CSV-formatted latency data suitable for plotting.
+
+The latency durations actually represent the midpoints of latency intervals.
+For details refer to stat.h.
+
+
.SH TRACE FILE FORMAT
There are two trace file format that you can encounter. The older (v1) format
is unsupported since version 1.20-rc3 (March 2008). It will still be described
projects / fio.git / blobdiff