Public bug reported: After updating to the latest kernel 5.0.0-15 I'm experiencing a severe performance degradation on my machine with one of my applications (a gbc emulator developed by me).
I saw about a 27% performance loss, going from 55fps to 40. Booting an old 5.0.0-13 kernel or disabling mds mitigation at boot with 'mds=off' solves the problem. I know there isn't much to do about (apart from disabling the mitigation) but I'm reporting this because I spent half a day bisecting with git cause I thought the problem was with my latest commits. Security updates are obviously important and a priority, but I think that at least with this kind of mitigations that cause big performance degradation, an message or a simple alert to the user during the update should be shown. Something like: "Plese be aware that this kernel update can result in performance loss. See this page for more info." and then link the specific SecurityTeam page (which in this case is https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/MDS ) ProblemType: Bug DistroRelease: Ubuntu 19.04 Package: linux-image-5.0.0-15-generic 5.0.0-15.16 ProcVersionSignature: Ubuntu 5.0.0-15.16-generic 5.0.6 Uname: Linux 5.0.0-15-generic x86_64 ApportVersion: 2.20.10-0ubuntu27 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: gabriele 2045 F.... pulseaudio /dev/snd/controlC1: gabriele 2045 F.... pulseaudio CurrentDesktop: ubuntu:GNOME Date: Wed May 15 16:36:36 2019 HibernationDevice: RESUME=UUID=e43b75a3-a278-4d4e-83e8-54a9e0c95276 InstallationDate: Installed on 2018-05-31 (349 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426) MachineType: Dell Inc. Latitude E6540 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.0.0-15-generic root=UUID=8a8a023d-2a12-4e14-b187-7beaf4d89763 ro quiet splash vt.handoff=1 RelatedPackageVersions: linux-restricted-modules-5.0.0-15-generic N/A linux-backports-modules-5.0.0-15-generic N/A linux-firmware 1.178 SourcePackage: linux UpgradeStatus: Upgraded to disco on 2019-04-23 (21 days ago) dmi.bios.date: 10/09/2018 dmi.bios.vendor: Dell Inc. dmi.bios.version: A26 dmi.board.name: 0725FP dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA26:bd10/09/2018:svnDellInc.:pnLatitudeE6540:pvr00:rvnDellInc.:rn0725FP:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.name: Latitude E6540 dmi.product.sku: 05BE dmi.product.version: 00 dmi.sys.vendor: Dell Inc. ** Affects: linux (Ubuntu) Importance: Undecided Status: Confirmed ** Tags: amd64 apport-bug disco -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1829255 Title: Sever performance degradation after updating to 5.0.0-15 due to mds mitigation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1829255/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
