Hi Stefan! On Wed 24-08-22 12:17:14, Stefan Wahren wrote: > Am 23.08.22 um 22:15 schrieb Jan Kara: > > Hello, > > > > So I have implemented mballoc improvements to avoid spreading allocations > > even with mb_optimize_scan=1. It fixes the performance regression I was able > > to reproduce with reaim on my test machine: > > > > mb_optimize_scan=0 mb_optimize_scan=1 patched > > Hmean disk-1 2076.12 ( 0.00%) 2099.37 ( 1.12%) 2032.52 ( -2.10%) > > Hmean disk-41 92481.20 ( 0.00%) 83787.47 * -9.40%* 90308.37 ( -2.35%) > > Hmean disk-81 155073.39 ( 0.00%) 135527.05 * -12.60%* 154285.71 ( -0.51%) > > Hmean disk-121 185109.64 ( 0.00%) 166284.93 * -10.17%* 185298.62 ( 0.10%) > > Hmean disk-161 229890.53 ( 0.00%) 207563.39 * -9.71%* 232883.32 * 1.30%* > > Hmean disk-201 223333.33 ( 0.00%) 203235.59 * -9.00%* 221446.93 ( -0.84%) > > Hmean disk-241 235735.25 ( 0.00%) 217705.51 * -7.65%* 239483.27 * 1.59%* > > Hmean disk-281 266772.15 ( 0.00%) 241132.72 * -9.61%* 263108.62 ( -1.37%) > > Hmean disk-321 265435.50 ( 0.00%) 245412.84 * -7.54%* 267277.27 ( 0.69%) > > > > Stefan, can you please test whether these patches fix the problem for you as > > well? Comments & review welcome. > > i tested the whole series against 5.19 and 6.0.0-rc2. In both cases the > update process succeed which is a improvement, but the download + unpack > duration ( ~ 7 minutes ) is not as good as with mb_optimize_scan=0 ( ~ 1 > minute ). OK, thanks for testing! I'll try to check specifically untar whether I can still see some differences in the IO pattern on my test machine. > Unfortuntately i don't have much time this week and next week i'm in > holidays. No problem. > Just a question, my tests always had MBCACHE=y . Is it possible that the > mb_optimize_scan is counterproductive for MBCACHE in this case? MBCACHE (despite similar name) is actually related to extended attributes so it likely has no impact on your workload. > I'm asking because before the download the update script removes the files > from the previous update process which already cause a high load. Do you mean already the removal step is noticeably slower with mb_optimize_scan=1? The removal will be modifying directory blocks, inode table blocks, block & inode bitmaps, and group descriptors. So if block allocations are more spread (due to mb_optimize_scan=1 used during the untar), the removal may also take somewhat longer. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
