-$ fio -o0 -s -b4096 -f file_with_above
-
-'global' is a reserved keyword. When used as the filename, it sets the
-default options for the threads following that section. It is possible
-to have more than one global section in the file, as it only affects
-subsequent jobs.
-
-Also see the examples/ dir for sample job files.
-
-
-Interpreting the output
------------------------
-
-fio spits out a lot of output. While running, fio will display the
-status of the jobs created. An example of that would be:
-
-Threads now running: 2 : [ww] [5.73% done]
-
-The characters inside the square brackets denote the current status of
-each thread. The possible values (in typical life cycle order) are:
-
-Idle Run
----- ---
-P Thread setup, but not started.
-C Thread created and running, but not doing anything yet
- R Running, doing sequential reads.
- r Running, doing random reads.
- W Running, doing sequential writes.
- w Running, doing random writes.
-V Running, doing verification of written data.
-E Thread exited, not reaped by main thread yet.
-_ Thread reaped.
-
-The other values are fairly self explanatory - number of thread currently
-running and doing io, and the estimated completion percentage.
-
-When fio is done (or interrupted by ctrl-c), it will show the data for
-each thread, group of threads, and disks in that order. For each data
-direction, the output looks like:
-
-Client1 (g=0): err= 0:
- write: io= 32MiB, bw= 666KiB/s, runt= 50320msec
- slat (msec): min= 0, max= 136, avg= 0.03, dev= 1.92
- clat (msec): min= 0, max= 631, avg=48.50, dev=86.82
- bw (KiB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, dev=681.68
- cpu : usr=1.49%, sys=0.25%, ctx=7969
-
-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,
-they denote:
-
-io= Number of megabytes io performed
-bw= Average bandwidth rate
-runt= The runtime of that thread
- slat= Submission latency (avg being the average, dev being the
- standard deviation). This is the time it took to submit
- the io. For sync io, the slat is really the completion
- latency, since queue/complete is one operation there.
- clat= Completion latency. Same names as slat, this denotes the
- time from submission to completion of the io pieces. For
- sync io, clat will usually be equal (or very close) to 0,
- as the time from submit to complete is basically just
- CPU time (io has already been done, see slat explanation).
- bw= Bandwidth. Same names as the xlat stats, but also includes
- an approximate percentage of total aggregate bandwidth
- this thread received in this group. This last value is
- only really useful if the threads in this group are on the
- same disk, since they are then competing for disk access.
-cpu= CPU usage. User and system time, along with the number
- of context switches this thread went through.
-
-After each client has been listed, the group statistics are printed. They
-will look like this:
-
-Run status group 0 (all jobs):
- READ: io=64MiB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec
- WRITE: io=64MiB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec
-
-For each data direction, it prints:
-
-io= Number of megabytes io performed.
-aggrb= Aggregate bandwidth of threads in this group.
-minb= The minimum average bandwidth a thread saw.
-maxb= The maximum average bandwidth a thread saw.
-mint= The minimum runtime of a thread.
-maxt= The maximum runtime of a thread.
-
-And finally, the disk statistics are printed. They will look like this:
-
-Disk stats (read/write):
- sda: ios=16398/16511, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00%
-
-Each value is printed for both reads and writes, with reads first. The
-numbers denote:
-
-ios= Number of ios performed by all groups.
-merge= Number of merges io the io scheduler.
-ticks= Number of ticks we kept the disk busy.
-io_queue= Total time spent in the disk queue.
-util= The disk utilization. A value of 100% means we kept the disk
- busy constantly, 50% would be a disk idling half of the time.