Improve accuracy of rate= option

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 2e4cdbdf146e17394a8ebcd481097e43846131ba..41edcf1a8ff820e09d915a4e69ceca11d8bb619c 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -981,7 +981,7 @@ verify_fatal=bool   Normally fio will keep checking the entire contents
 verify_dump=bool       If set, dump the contents of both the original data
                block and the data block we read off disk to files. This
                allows later analysis to inspect just what kind of data
-               corruption occurred. On by default.
+               corruption occurred. Off by default.
 
 verify_async=int       Fio will normally verify IO inline from the submitting
                thread. This option takes an integer describing how many
@@ -1360,27 +1360,43 @@ signify that change.
 
 Split up, the format is as follows:
 
-       version, jobname, groupid, error
+       terse version, fio version, jobname, groupid, error
        READ status:
-               Total IO (KB), bandwidth (KB/sec), runtime (msec)
+               Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
                Submission latency: min, max, mean, deviation
                Completion latency: min, max, mean, deviation
+               Completion latency percentiles: 20 fields (see below)
                Total latency: min, max, mean, deviation
                Bw: min, max, aggregate percentage of total, mean, deviation
        WRITE status:
-               Total IO (KB), bandwidth (KB/sec), runtime (msec)
+               Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
                Submission latency: min, max, mean, deviation
                Completion latency: min, max, mean, deviation
+               Completion latency percentiles: 20 fields (see below)
                Total latency: min, max, mean, deviation
                Bw: min, max, aggregate percentage of total, mean, deviation
        CPU usage: user, system, context switches, major faults, minor faults
        IO depths: <=1, 2, 4, 8, 16, 32, >=64
        IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
        IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
+       Disk utilization: Disk name, Read ios, write ios,
+                         Read merges, write merges,
+                         Read ticks, write ticks,
+                         Time spent in queue, disk utilization percentage
        Additional Info (dependant on continue_on_error, default off): total # errors, first error code 
        
        Additional Info (dependant on description being set): Text description
 
+Completion latency percentiles can be a grouping of up to 20 sets, so
+for the terse output fio writes all of them. Each field will look like this:
+
+       1.00%=6112
+
+which is the Xth percentile, and the usec latency associated with it.
+
+For disk utilization, all disks used by fio are shown. So for each disk
+there will be a disk utilization section.
+
 
 8.0 Trace file format
 ---------------------