A global section sets defaults for the jobs described in that file. A job
may override a global section parameter, and a job file may even have
several global sections if so desired. A job is only affected by a global
-section residing above it. If the first character in a line is a ';', the
-entire line is discarded as a comment.
+section residing above it. If the first character in a line is a ';' or a
+'#', the entire line is discarded as a comment.
So lets look at a really simple job file that define to threads, each
randomly reading from a 128MiB file.
job, can be overridden with a larger value for higher
concurrency.
+iodepth_low=int The low water mark indicating when to start filling
+ the queue again. Defaults to the same as iodepth, meaning
+ that fio will attempt to keep the queue full at all times.
+ If iodepth is set to eg 16 and iodepth_low is set to 4, then
+ after fio has filled the queue of 16 requests, it will let
+ the depth drain down to 4 before starting to fill it again.
+
direct=bool If value is true, use non-buffered io. This is usually
O_DIRECT.
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%
+ lat (msec): 2=1.6%, 4=0.0%, 10=3.2%, 20=12.8%, 50=38.4%, 100=24.8%,
+ lat (msec): 250=15.2%, 500=0.0%, 750=0.0%, 1000=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,
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.
+ within 2 msecs, 20=12.8% means that 12.8% of the IO
+ took more than 10 msecs, but less than (or equal to) 20 msecs.
After each client has been listed, the group statistics are printed. They
will look like this: