Hi Sasha! On Wed, Dec 21, 2011 at 10:28:52AM +0200, Sasha Levin wrote: > On Wed, 2011-12-21 at 10:00 +0900, Minchan Kim wrote: > > This patch is follow-up of Christohp Hellwig's work > > [RFC: ->make_request support for virtio-blk]. > > http://thread.gmane.org/gmane.linux.kernel/1199763 > > > > Quote from hch > > "This patchset allows the virtio-blk driver to support much higher IOP > > rates which can be driven out of modern PCI-e flash devices. At this > > point it really is just a RFC due to various issues." > > > > I fixed race bug and add batch I/O for enhancing sequential I/O, > > FLUSH/FUA emulation. > > > > I tested this patch on fusion I/O device by aio-stress. > > Result is following as. > > > > Benchmark : aio-stress (64 thread, test file size 512M, 8K io per IO, O_DIRECT write) > > Environment: 8 socket - 8 core, 2533.372Hz, Fusion IO 320G storage > > Test repeated by 20 times > > Guest I/O scheduler : CFQ > > Host I/O scheduler : NOOP > > > > Request BIO(patch 1-4) BIO-batch(patch 1-6) > > (MB/s) stddev (MB/s) stddev (MB/s) stddev > > w 737.820 4.063 613.735 31.605 730.288 24.854 > > rw 208.754 20.450 314.630 37.352 317.831 41.719 > > r 770.974 2.340 347.483 51.370 750.324 8.280 > > rr 250.391 16.910 350.053 29.986 325.976 24.846 > > > > This patch enhances ramdom I/O performance compared to request-based I/O path. > > It's still RFC so welcome to any comment and review. > > I did a benchmark against a /dev/shm device instead of an actual storage > to get rid of any artifacts which are caused by the storage itself, and > saw that while there was a nice improvement across the board, the hit > against sequential read and write was quite significant. Hmm, it seems bandwidth test of sequential is bad but io test is still good. I don't know how it is possbile that iops is better but bandwidth is bad. Anyway, it seems sequential write bw is severe but I think it could be better if test makes many lock overhead in vblk->lock because this patch is started from the lock overhead. Thanks for the testing, Sasha! > > I ran the tests with fio running in KVM tool against a 2G file located > in /dev/shm. Here is a summary of the results: > > Before: > write_iops_seq > write: io=1409.8MB, bw=144217KB/s, iops=36054 , runt= 10010msec > write_bw_seq > write: io=7700.0MB, bw=1323.5MB/s, iops=1323 , runt= 5818msec > read_iops_seq > read : io=1453.7MB, bw=148672KB/s, iops=37168 , runt= 10012msec > read_bw_seq > read : io=7700.0MB, bw=1882.7MB/s, iops=1882 , runt= 4090msec > write_iops_rand > write: io=1266.4MB, bw=129479KB/s, iops=32369 , runt= 10015msec > write_bw_rand > write: io=7539.0MB, bw=1106.1MB/s, iops=1106 , runt= 6811msec > read_iops_rand > read : io=1373.3MB, bw=140475KB/s, iops=35118 , runt= 10010msec > read_bw_rand > read : io=7539.0MB, bw=1314.4MB/s, iops=1314 , runt= 5736msec > readwrite_iops_seq > read : io=726172KB, bw=72292KB/s, iops=18072 , runt= 10045msec > write: io=726460KB, bw=72321KB/s, iops=18080 , runt= 10045msec > readwrite_bw_seq > read : io=3856.0MB, bw=779574KB/s, iops=761 , runt= 5065msec > write: io=3844.0MB, bw=777148KB/s, iops=758 , runt= 5065msec > readwrite_iops_rand > read : io=701780KB, bw=70094KB/s, iops=17523 , runt= 10012msec > write: io=706120KB, bw=70527KB/s, iops=17631 , runt= 10012msec > readwrite_bw_rand > read : io=3705.0MB, bw=601446KB/s, iops=587 , runt= 6308msec > write: io=3834.0MB, bw=622387KB/s, iops=607 , runt= 6308msec > > After: > write_iops_seq > write: io=1591.4MB, bw=162626KB/s, iops=40656 , runt= 10020msec > write_bw_seq > write: io=7700.0MB, bw=1276.4MB/s, iops=1276 , runt= 6033msec > read_iops_seq > read : io=1615.7MB, bw=164680KB/s, iops=41170 , runt= 10046msec > read_bw_seq > read : io=7700.0MB, bw=1407.1MB/s, iops=1407 , runt= 5469msec > write_iops_rand > write: io=1243.1MB, bw=126304KB/s, iops=31575 , runt= 10085msec > write_bw_rand > write: io=7539.0MB, bw=1206.3MB/s, iops=1206 , runt= 6250msec > read_iops_rand > read : io=1533.1MB, bw=156795KB/s, iops=39198 , runt= 10018msec > read_bw_rand > read : io=7539.0MB, bw=1413.7MB/s, iops=1413 , runt= 5333msec > readwrite_iops_seq > read : io=819124KB, bw=81790KB/s, iops=20447 , runt= 10015msec > write: io=823136KB, bw=82190KB/s, iops=20547 , runt= 10015msec > readwrite_bw_seq > read : io=3913.0MB, bw=704946KB/s, iops=688 , runt= 5684msec > write: io=3787.0MB, bw=682246KB/s, iops=666 , runt= 5684msec > readwrite_iops_rand > read : io=802148KB, bw=80159KB/s, iops=20039 , runt= 10007msec > write: io=801192KB, bw=80063KB/s, iops=20015 , runt= 10007msec > readwrite_bw_rand > read : io=3731.0MB, bw=677762KB/s, iops=661 , runt= 5637msec > write: io=3808.0MB, bw=691750KB/s, iops=675 , runt= 5637msec > > -- > > Sasha. > > -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
