Chaitanya Kulkarni wrote: > Allow user to set the QUEUE_FLAG_NOWAIT optionally using module > parameter to retain the default behaviour. Also, update respective > allocation flags in the write path. Following are the performance > numbers with io_uring fio engine for random read, note that device has > been populated fully with randwrite workload before taking these > numbers :-
Numbers look good. I see no reason for this to be optional. Just like the brd driver always sets NOWAIT, so should pmem. > > * linux-block (for-next) # grep IOPS pmem*fio | column -t > > nowait-off-1.fio: read: IOPS=3968k, BW=15.1GiB/s > nowait-off-2.fio: read: IOPS=4084k, BW=15.6GiB/s > nowait-off-3.fio: read: IOPS=3995k, BW=15.2GiB/s > > nowait-on-1.fio: read: IOPS=5909k, BW=22.5GiB/s > nowait-on-2.fio: read: IOPS=5997k, BW=22.9GiB/s > nowait-on-3.fio: read: IOPS=6006k, BW=22.9GiB/s > > * linux-block (for-next) # grep cpu pmem*fio | column -t > > nowait-off-1.fio: cpu : usr=6.38%, sys=31.37%, ctx=220427659 > nowait-off-2.fio: cpu : usr=6.19%, sys=31.45%, ctx=229825635 > nowait-off-3.fio: cpu : usr=6.17%, sys=31.22%, ctx=221896158 > > nowait-on-1.fio: cpu : usr=10.56%, sys=87.82%, ctx=24730 > nowait-on-2.fio: cpu : usr=9.92%, sys=88.36%, ctx=23427 > nowait-on-3.fio: cpu : usr=9.85%, sys=89.04%, ctx=23237 > > * linux-block (for-next) # grep slat pmem*fio | column -t > nowait-off-1.fio: slat (nsec): min=431, max=50423k, avg=9424.06 > nowait-off-2.fio: slat (nsec): min=420, max=35992k, avg=9193.94 > nowait-off-3.fio: slat (nsec): min=430, max=40737k, avg=9244.24 > > nowait-on-1.fio: slat (nsec): min=1232, max=40098k, avg=7518.60 > nowait-on-2.fio: slat (nsec): min=1303, max=52107k, avg=7423.37 > nowait-on-3.fio: slat (nsec): min=1123, max=40193k, avg=7409.08 Any thoughts on why min latency went up?
