Using ramp_time is causing all min values (slat/clat/lat/bw/iops) to report 0.
Removing ramp_time fixes the issue.
Job file:
[rnd-8020]
ioengine=libaio
direct=1
bs=4k
rw=randrw
rwmixread=80
numjobs=1
iodepth=32
runtime=10
time_based
norandommap
randrepeat=0
filename=/dev/sdb
#ramp_time=10
Fio output with min values zeroed:
rnd-8020: (g=0): rw=randrw, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
4096B-4096B, ioengine=libaio, iodepth=32
fio-3.12-45-g771c
Starting 1 process
Jobs: 1 (f=1): [m(1)][100.0%][r=149MiB/s,w=37.4MiB/s][r=38.1k,w=9562
IOPS][eta 00m:00s]
rnd-8020: (groupid=0, jobs=1): err= 0: pid=4701: Thu Dec 13 14:14:36 2018
read: IOPS=33.6k, BW=131MiB/s (138MB/s)(1313MiB/10002msec)
slat (nsec): min=0, max=14301, avg=1880.55, stdev=242.49
clat (nsec): min=0, max=9948.1k, avg=633109.98, stdev=597207.47
lat (nsec): min=0, max=9950.0k, avg=635050.69, stdev=597212.18
clat percentiles (usec):
| 1.00th=[ 135], 5.00th=[ 165], 10.00th=[ 178], 20.00th=[ 202],
| 30.00th=[ 227], 40.00th=[ 251], 50.00th=[ 285], 60.00th=[ 379],
| 70.00th=[ 873], 80.00th=[ 1270], 90.00th=[ 1565], 95.00th=[ 1762],
| 99.00th=[ 2212], 99.50th=[ 2606], 99.90th=[ 3851], 99.95th=[ 4015],
| 99.99th=[ 5211]
bw ( KiB/s): min= 0, max=164608, per=100.00%, avg=134473.20,
stdev=12836.10, samples=20
iops : min= 0, max=41152, avg=33618.30, stdev=3209.03, samples=20
write: IOPS=8419, BW=32.9MiB/s (34.5MB/s)(329MiB/10002msec); 0 zone resets
slat (nsec): min=0, max=13697, avg=2059.16, stdev=383.41
clat (nsec): min=0, max=10090k, avg=1261001.47, stdev=575428.55
lat (nsec): min=0, max=10092k, avg=1263121.22, stdev=575424.23
clat percentiles (usec):
| 1.00th=[ 474], 5.00th=[ 635], 10.00th=[ 709], 20.00th=[ 807],
| 30.00th=[ 898], 40.00th=[ 996], 50.00th=[ 1106], 60.00th=[ 1237],
| 70.00th=[ 1418], 80.00th=[ 1680], 90.00th=[ 2089], 95.00th=[ 2376],
| 99.00th=[ 3064], 99.50th=[ 3523], 99.90th=[ 4424], 99.95th=[ 4752],
| 99.99th=[ 5866]
bw ( KiB/s): min= 0, max=40240, per=100.00%, avg=33682.40,
stdev=3069.64, samples=20
iops : min= 0, max=10060, avg=8420.60, stdev=767.41, samples=20
lat (usec) : 100=0.20%, 250=31.37%, 500=20.39%, 750=5.34%, 1000=8.79%
lat (msec) : 2=30.07%, 4=3.76%, 10=0.08%, 20=0.01%
cpu : usr=9.58%, sys=12.38%, ctx=406871, majf=0, minf=15
IO depths : 1=0.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=100.0%, >=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=0.0%, 32=0.1%, 64=0.0%, >=64=0.0%
issued rwts: total=336181,84209,0,0 short=0,0,0,0 dropped=0,0,0,0
latency : target=0, window=0, percentile=100.00%, depth=32
