ssd – Latency in fio vs ioping


There are two tests:

ioping -c 10 -S 4K .

9 requests completed in 2.49 ms, 36 KiB read, 3.61 k iops, 14.1 MiB/s
generated 10 requests in 9.00 s, 40 KiB, 1 iops, 4.44 KiB/s
min/avg/max/mdev = 259.5 us / 277.0 us / 325.0 us / 19.9 us
sudo fio --ioengine=libaio --direct=1 --rw=read --bs=4K --numjobs=1 --iodepth=1 --runtime=10 --time_based --name seq_read --filename=/fiotest --size=100m

 read: IOPS=19.8k, BW=77.5MiB/s (81.2MB/s)(775MiB/10001msec)
clat (nsec): min=830, max=11311k, avg=44909.47, stdev=76899.23

Both use the same block size, but the results of latency and iops are completly different. Why so?