Verify requeue handling

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index e5b09fd6af18b11877aeb00a51c8fc84477afad3..8e6e29bbc7dd98e6eb9857596c02de03ebdd0635 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -343,7 +343,14 @@ prioclass=int      Set the io priority class. See man ionice(1).
 
 thinktime=int  Stall the job x microseconds after an io has completed before
                issuing the next. May be used to simulate processing being
 
 thinktime=int  Stall the job x microseconds after an io has completed before
                issuing the next. May be used to simulate processing being

-               done by an application. See thinktime_blocks.
+               done by an application. See thinktime_blocks and
+               thinktime_spin.
+
+thinktime_spin=int
+               Only valid if thinktime is set - pretend to spend CPU time
+               doing something with the data received, before falling back
+               to sleeping for the rest of the period specified by
+               thinktime.

 
 thinktime_blocks
                Only valid if thinktime is set - control how many blocks
 
 thinktime_blocks
                Only valid if thinktime is set - control how many blocks


@@ -556,6 +563,8 @@ Client1 (g=0): err= 0:
     bw (KiB/s) : min=    0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
   cpu        : usr=1.49%, sys=0.25%, ctx=7969
   IO depths    : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0%
     bw (KiB/s) : min=    0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
   cpu        : usr=1.49%, sys=0.25%, ctx=7969
   IO depths    : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0%

+     lat (msec): 2=1.6%, 4=0.0%, 8=3.2%, 16=12.8%, 32=38.4%, 64=24.8%, 128=15.2%
+     lat (msec): 256=4.0%, 512=0.0%, 1024=0.0%, >=2048=0.0%

 
 The client number is printed, along with the group id and error of that
 thread. Below is the io statistics, here for writes. In the order listed,
 
 The client number is printed, along with the group id and error of that
 thread. Below is the io statistics, here for writes. In the order listed,


@@ -585,6 +594,12 @@ IO depths= The distribution of io depths over the job life time. The
                16= entries includes depths up to that value but higher
                than the previous entry. In other words, it covers the
                range from 16 to 31.
                16= entries includes depths up to that value but higher
                than the previous entry. In other words, it covers the
                range from 16 to 31.

+IO latencies=  The distribution of IO completion latencies. This is the
+               time from when IO leaves fio and when it gets completed.
+               The numbers follow the same pattern as the IO depths,
+               meaning that 2=1.6% means that 1.6% of the IO completed
+               within 2 msecs, 16=12.8% means that 12.8% of the IO
+               took more than 8 msecs, but less than (or equal to) 16 msecs.

 
 After each client has been listed, the group statistics are printed. They
 will look like this:
 
 After each client has been listed, the group statistics are printed. They
 will look like this: