Hi, > Hi Wang Yugui, > > On Sun, May 28, 2023 at 5:53?PM Wang Yugui <wangyugui@xxxxxxxxxxxx> wrote: > > Hi, > > > > > Hi, > > > > > > gfs2 write bandwidth regression on 6.4-rc3 compare to 5.15.y. > > > > > > we added linux-xfs@ and linux-fsdevel@ because some related problem[1] > > > and related patches[2]. > > > > > > we compared 6.4-rc3(rather than 6.1.y) to 5.15.y because some related patches[2] > > > work only for 6.4 now. > > > > > > [1] https://lore.kernel.org/linux-xfs/20230508172406.1CF3.409509F4@xxxxxxxxxxxx/ > > > [2] https://lore.kernel.org/linux-xfs/20230520163603.1794256-1-willy@xxxxxxxxxxxxx/ > > > > > > > > > test case: > > > 1) PCIe3 SSD *4 with LVM > > > 2) gfs2 lock_nolock > > > gfs2 attr(T) GFS2_AF_ORLOV > > > # chattr +T /mnt/test > > > 3) fio > > > fio --name=global --rw=write -bs=1024Ki -size=32Gi -runtime=30 -iodepth 1 > > > -ioengine sync -zero_buffers=1 -direct=0 -end_fsync=1 -numjobs=1 \ > > > -name write-bandwidth-1 -filename=/mnt/test/sub1/1.txt \ > > > -name write-bandwidth-2 -filename=/mnt/test/sub2/1.txt \ > > > -name write-bandwidth-3 -filename=/mnt/test/sub3/1.txt \ > > > -name write-bandwidth-4 -filename=/mnt/test/sub4/1.txt > > > 4) patches[2] are applied to 6.4-rc3. > > > > > > > > > 5.15.y result > > > fio WRITE: bw=5139MiB/s (5389MB/s), > > > 6.4-rc3 result > > > fio WRITE: bw=2599MiB/s (2725MB/s) > > > > more test result: > > > > 5.17.0 WRITE: bw=4988MiB/s (5231MB/s) > > 5.18.0 WRITE: bw=5165MiB/s (5416MB/s) > > 5.19.0 WRITE: bw=5511MiB/s (5779MB/s) > > 6.0.5 WRITE: bw=3055MiB/s (3203MB/s), WRITE: bw=3225MiB/s (3382MB/s) > > 6.1.30 WRITE: bw=2579MiB/s (2705MB/s) > > > > so this regression happen in some code introduced in 6.0, > > and maybe some minor regression in 6.1 too? > > thanks for this bug report. Bob has noticed a similar looking > performance regression recently, and it turned out that commit > e1fa9ea85ce8 ("gfs2: Stop using glock holder auto-demotion for now") > inadvertently caused buffered writes to fall back to writing single > pages instead of multiple pages at once. That patch was added in > v5.18, so it doesn't perfectly align with the regression history > you're reporting, but maybe there's something else going on that we're > not aware of. > > In any case, the regression introduced by commit e1fa9ea85ce8 should > be fixed by commit c8ed1b359312 ("gfs2: Fix duplicate > should_fault_in_pages() call"), which ended up in v6.5-rc1. > > Could you please check where we end up with that fix? I applied c8ed1b359312 on 6.1.36. # the build/test of 6.5-rc1 is yet not ready. fio performance result: WRITE: bw=2683MiB/s (2813MB/s) but the performance of fio 'Laying out IO file' is improved. Jobs: 4 (f=4): [F(4)][100.0%][w=5168MiB/s][w=5168 IOPS][eta 00m:00s] so there seems 2 problems, one is fixed by c8ed1b359312. but another is still left. Best Regards Wang Yugui (wangyugui@xxxxxxxxxxxx) 2023/07/11
