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** Changed in: linux (Ubuntu)
Status: New => Confirmed
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https://bugs.launchpad.net/bugs/1829255
Title:
Sever performance degradation after updating to 5.0.0-15 due to mds
mitigation
Status in linux package in Ubuntu:
Confirmed
Bug description:
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.
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