On Wed, Mar 09, 2022 at 09:11:26AM -0700, Jens Axboe wrote: > On 3/8/22 6:13 PM, Ming Lei wrote: > > On Tue, Mar 08, 2022 at 06:02:50PM -0700, Jens Axboe wrote: > >> On 3/7/22 11:53 AM, Mike Snitzer wrote: > >>> From: Ming Lei <ming.lei@xxxxxxxxxx> > >>> > >>> Support bio(REQ_POLLED) polling in the following approach: > >>> > >>> 1) only support io polling on normal READ/WRITE, and other abnormal IOs > >>> still fallback to IRQ mode, so the target io is exactly inside the dm > >>> io. > >>> > >>> 2) hold one refcnt on io->io_count after submitting this dm bio with > >>> REQ_POLLED > >>> > >>> 3) support dm native bio splitting, any dm io instance associated with > >>> current bio will be added into one list which head is bio->bi_private > >>> which will be recovered before ending this bio > >>> > >>> 4) implement .poll_bio() callback, call bio_poll() on the single target > >>> bio inside the dm io which is retrieved via bio->bi_bio_drv_data; call > >>> dm_io_dec_pending() after the target io is done in .poll_bio() > >>> > >>> 5) enable QUEUE_FLAG_POLL if all underlying queues enable QUEUE_FLAG_POLL, > >>> which is based on Jeffle's previous patch. > >> > >> It's not the prettiest thing in the world with the overlay on bi_private, > >> but at least it's nicely documented now. > >> > >> I would encourage you to actually test this on fast storage, should make > >> a nice difference. I can run this on a gen2 optane, it's 10x the IOPS > >> of what it was tested on and should help better highlight where it > >> makes a difference. > >> > >> If either of you would like that, then send me a fool proof recipe for > >> what should be setup so I have a poll capable dm device. > > > > Follows steps for setup dm stripe over two nvmes, then run io_uring on > > the dm stripe dev. > > Thanks! Much easier when I don't have to figure it out... Setup: Jens, thanks for running the test! > > CPU: 12900K > Drives: 2x P5800X gen2 optane (~5M IOPS each at 512b) > > Baseline kernel: > > sudo taskset -c 10 t/io_uring -d128 -b512 -s31 -c16 -p1 -F1 -B1 -n1 -R1 -X1 /dev/dm-0 > Added file /dev/dm-0 (submitter 0) > polled=1, fixedbufs=1/0, register_files=1, buffered=0, QD=128 > Engine=io_uring, sq_ring=128, cq_ring=128 > submitter=0, tid=1004 > IOPS=2794K, BW=1364MiB/s, IOS/call=31/30, inflight=(124) > IOPS=2793K, BW=1363MiB/s, IOS/call=31/31, inflight=(62) > IOPS=2789K, BW=1362MiB/s, IOS/call=31/30, inflight=(124) > IOPS=2779K, BW=1357MiB/s, IOS/call=31/31, inflight=(124) > IOPS=2780K, BW=1357MiB/s, IOS/call=31/31, inflight=(62) > IOPS=2779K, BW=1357MiB/s, IOS/call=31/31, inflight=(62) > ^CExiting on signal > Maximum IOPS=2794K > > generating about 500K ints/sec, ~5.6 IOs completed in each int averagely, looks irq coalesce is working. > and using 4k blocks: > > sudo taskset -c 10 t/io_uring -d128 -b4096 -s31 -c16 -p1 -F1 -B1 -n1 -R1 -X1 /dev/dm-0 > Added file /dev/dm-0 (submitter 0) > polled=1, fixedbufs=1/0, register_files=1, buffered=0, QD=128 > Engine=io_uring, sq_ring=128, cq_ring=128 > submitter=0, tid=967 > IOPS=1683K, BW=6575MiB/s, IOS/call=24/24, inflight=(93) > IOPS=1685K, BW=6584MiB/s, IOS/call=24/24, inflight=(124) > IOPS=1686K, BW=6588MiB/s, IOS/call=24/24, inflight=(124) > IOPS=1684K, BW=6581MiB/s, IOS/call=24/24, inflight=(93) > IOPS=1686K, BW=6589MiB/s, IOS/call=24/24, inflight=(124) > IOPS=1687K, BW=6593MiB/s, IOS/call=24/24, inflight=(128) > IOPS=1687K, BW=6590MiB/s, IOS/call=24/24, inflight=(93) > ^CExiting on signal > Maximum IOPS=1687K > > which ends up being bw limited for me, because the devices aren't linked > gen4. That's about 1.4M ints/sec. Looks one interrupt just completes one IO with 4k bs, no irq coalesce any more. The interrupts may not run in CPU 10 I guess. > > With the patched kernel, same test: > > sudo taskset -c 10 t/io_uring -d128 -b512 -s31 -c16 -p1 -F1 -B1 -n1 -R1 -X1 /dev/dm-0 > Added file /dev/dm-0 (submitter 0) > polled=1, fixedbufs=1/0, register_files=1, buffered=0, QD=128 > Engine=io_uring, sq_ring=128, cq_ring=128 > submitter=0, tid=989 > IOPS=4151K, BW=2026MiB/s, IOS/call=16/15, inflight=(128) > IOPS=4159K, BW=2031MiB/s, IOS/call=15/15, inflight=(128) > IOPS=4193K, BW=2047MiB/s, IOS/call=15/15, inflight=(128) > IOPS=4191K, BW=2046MiB/s, IOS/call=15/15, inflight=(128) > IOPS=4202K, BW=2052MiB/s, IOS/call=15/15, inflight=(128) > ^CExiting on signal > Maximum IOPS=4202K > > with basically zero interrupts, and 4k: > > sudo taskset -c 10 t/io_uring -d128 -b4096 -s31 -c16 -p1 -F1 -B1 -n1 -R1 -X1 /dev/dm-0 > Added file /dev/dm-0 (submitter 0) > polled=1, fixedbufs=1/0, register_files=1, buffered=0, QD=128 > Engine=io_uring, sq_ring=128, cq_ring=128 > submitter=0, tid=1015 > IOPS=1706K, BW=6666MiB/s, IOS/call=15/15, inflight=(128) > IOPS=1704K, BW=6658MiB/s, IOS/call=15/15, inflight=(128) > IOPS=1704K, BW=6658MiB/s, IOS/call=15/15, inflight=(128) > IOPS=1704K, BW=6658MiB/s, IOS/call=15/15, inflight=(128) > IOPS=1704K, BW=6658MiB/s, IOS/call=15/15, inflight=(128) > ^CExiting on signal > Maximum IOPS=1706K Looks improvement on 4k is small, is it caused by pcie bw limit? What is the IOPS when running the same t/io_uring on single optane directly? Thanks, Ming -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel
