~# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=16 --size=4G --readwrite=randread

test: (groupid=0, jobs=1): err= 0: pid=17457: Thu Sep 3 12:39:10 2015
read : io=0B, bw=115612KB/s, iops=28903, runt= 36279msec
cpu : usr=17.12%, sys=67.12%, ctx=35506, majf=0, minf=39
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=100.0%, 32=0.0%, >=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.1%, 32=0.0%, 64=0.0%, >=64=0.0%
issued : total=r=1048576/w=0/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
READ: io=4096.0MB, aggrb=115612KB/s, minb=115612KB/s, maxb=115612KB/s, mint=36279msec, maxt=36279msec

Disk stats (read/write):
nbd0: ios=55484/53, merge=0/587, ticks=134950/1020, in_queue=135900, util=24.02%

~# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=16 --size=4G --readwrite=randwrite

test: (groupid=0, jobs=1): err= 0: pid=17460: Thu Sep 3 12:43:54 2015
write: io=0B, bw=15741KB/s, iops=3935, runt=266460msec
cpu : usr=3.97%, sys=25.75%, ctx=544104, majf=0, minf=23
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=100.0%, 32=0.0%, >=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.1%, 32=0.0%, 64=0.0%, >=64=0.0%
issued : total=r=0/w=1048576/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
WRITE: io=4096.0MB, aggrb=15740KB/s, minb=15740KB/s, maxb=15740KB/s, mint=266460msec, maxt=266460msec

Disk stats (read/write):
nbd0: ios=0/1053524, merge=0/106948, ticks=0/4282740, in_queue=4281210, util=100.00%

~# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=128 --size=4G --readwrite=randwrite

test: (groupid=0, jobs=1): err= 0: pid=17463: Thu Sep 3 12:48:26 2015
write: io=0B, bw=16400KB/s, iops=4100, runt=255749msec
cpu : usr=4.20%, sys=22.28%, ctx=576266, majf=0, minf=23
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.1%
issued : total=r=0/w=1048576/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
WRITE: io=4096.0MB, aggrb=16400KB/s, minb=16400KB/s, maxb=16400KB/s, mint=255749msec, maxt=255749msec

Disk stats (read/write):
nbd0: ios=0/1047606, merge=0/56, ticks=0/32543280, in_queue=32545150, util=100.00%

~# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=128 --size=4G --readwrite=randread

test: (groupid=0, jobs=1): err= 0: pid=9439: Thu Sep 3 12:48:32 2015
read : io=0B, bw=28594KB/s, iops=7148, runt=146685msec
cpu : usr=8.60%, sys=31.77%, ctx=591701, majf=0, minf=138
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.1%
issued : total=r=1048576/w=0/d=0, short=r=0/w=0/d=0
latency : target=0, window=0, percentile=100.00%, depth=128

Run status group 0 (all jobs):
READ: io=4096.0MB, aggrb=28593KB/s, minb=28593KB/s, maxb=28593KB/s, mint=146685msec, maxt=146685msec

Disk stats (read/write):
nbd0: ios=1047291/4, merge=0/1, ticks=18660030/50, in_queue=18659150, util=100.00%