** Summary changed: - 18.04: Raid5 performances on kernel 4.15 are suboptimal + 18.04: Raid performances on kernel 4.15 and newer are suboptimal when used on NVMe devices
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1815178 Title: 18.04: Raid performances on kernel 4.15 and newer are suboptimal when used on NVMe devices Status in linux package in Ubuntu: Confirmed Bug description: Hello, We have been running multiple tests using the md driver to build various type of RAID devices. Performances on RAID5 are particularly disappointing so we would like to know if there are any known issue with the md driver on Bionic kernels. Here are some of our results : Test (Threads) QCT JBODQCT RAID5 (8 threads) QCT RAID10 read(1) 838 751 (-10%) 572 (-32%) read(2) 1226 1172 (-4%) 1057 (-14%) read(4) 1129 2006 (+78%) 1760 (+56%) write(1) 804 382 (-52%) 398 (-50%) write(2) 1047 175 (-83%) 667 (-36%) write(4) 883 415 (-53%) 871 (-1%) randread(1) 863 749 (-13%) 619 (-28%) randread(2) 1346 1067 (-21%) 1020 (-24%) randread(4) 1648 1785 (+8%) 1650 (=) randwrite(1) 766 287 (-63%) 391 (-50%) randwrite(2) 1044 313 (-70%) 664 (-36%) randwrite(4) 916 282 (-69%) 885 (-3%) We are preparing tests with one of the latest mainline kernel. TIA, ...Louis To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1815178/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
