Hi Jens, Dexuan, On Tue, Dec 28, 2021 at 10:30:43AM +0800, Yin Fengwei wrote: > Hi Jens, Dexuan, > > On 12/20/2021 1:15 PM, Dexuan Cui wrote: > >> From: Jens Axboe > >> Sent: Sunday, December 19, 2021 7:28 AM > >>> ... > >>> Dexuan, can you test this for your test case too? I'm going to queue > >>> up a revert for -rc6 just in case. > >> > >> This one should be better... > >> ... > >> Jens Axboe > > > > Hi Jens, sorry -- unluckily I lost the test environment.. :-( > > I pinged the user to set up the test environment again, but he's > > on vacation till the beginning of January. > > We hit this issue in our testing env also and will help to verify > your fixing patch. Thanks. as we reported in [1], we found cb2ac2912a cause big regressions in fxmark tests. "[block] cb2ac2912a: fxmark.ssd_f2fs_dbench_client_4_bufferedio.works/sec -66.0% regression" By applying the patch supplied by Jens Axboe in previous thread directly upon cb2ac2912a, we confirmed the regression could be fixed: ========================================================================================= compiler/cpufreq_governor/directio/disk/fstype/kconfig/media/rootfs/tbox_group/test/testcase/ucode: gcc-9/performance/bufferedio/1SSD/f2fs/x86_64-rhel-8.3/ssd/debian-10.4-x86_64-20200603.cgz/lkp-snr-a1/dbench_client/fxmark/0x9c02000e commit: edaa26334c ("iocost: Fix divide-by-zero on donation from low hweight cgroup") cb2ac2912a ("block: reduce kblockd_mod_delayed_work_on() CPU consumption") 80f0eab183 (fix for very low IOPS due to "block: reduce kblockd_mod_delayed_work_on() CPU consumption") <-- patch by Jens Axboe edaa26334c117a58 cb2ac2912a9ca7d3d26291c5119 80f0eab18356919a1c0568c6348 ---------------- --------------------------- --------------------------- %stddev %change %stddev %change %stddev \ | \ | \ 573.42 -66.0% 194.68 -0.6% 570.11 fxmark.ssd_f2fs_dbench_client_4_bufferedio.works/sec actually there are other subtests which either have regressions also fixed by new patch, or we didn't observe obvious performance changes. edaa26334c117a58 cb2ac2912a9ca7d3d26291c5119 80f0eab18356919a1c0568c6348 ---------------- --------------------------- --------------------------- %stddev %change %stddev %change %stddev \ | \ | \ 574.25 -18.5% 468.11 -0.4% 571.83 fxmark.ssd_f2fs_dbench_client_18_bufferedio.works/sec 495.79 +0.2% 496.65 -0.6% 493.04 fxmark.ssd_f2fs_dbench_client_1_bufferedio.works/sec 536.81 -72.8% 145.99 ± 19% -0.6% 533.78 fxmark.ssd_f2fs_dbench_client_2_bufferedio.works/sec 544.81 +1.8% 554.73 -0.1% 544.26 fxmark.ssd_f2fs_dbench_client_36_bufferedio.works/sec 513.26 ± 2% +2.5% 526.05 ± 3% -1.8% 504.04 fxmark.ssd_f2fs_dbench_client_54_bufferedio.works/sec 513.10 ± 4% +3.9% 533.07 ± 3% -0.7% 509.73 ± 5% fxmark.ssd_f2fs_dbench_client_72_bufferedio.works/sec also attached detail comparison table edaa26334c-cb2ac2912a-80f0eab183 which contains futher details such like perf data. [1] https://lore.kernel.org/lkml/20211219141852.GH14057@xsang-OptiPlex-9020/ > > > Regards > Yin, Fengwei