This change was made by a bot.
** Changed in: linux (Ubuntu)
Status: New => Confirmed
--
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/1779305
Title:
Sluggish performance as Xen dom0
Status in linux package in Ubuntu:
Confirmed
Status in linux-signed-hwe-edge package in Ubuntu:
New
Bug description:
1) The release of Ubuntu you are using, via 'lsb_release -rd' or
System -> About Ubuntu
16.04 LTS
2) The version of the package you are using, via 'apt-cache policy
pkgname' or by checking in Software Center
Tried booting various versions between the 4.13.0-lowlatency and
4.15.0-lowlatency versions.
Can confirm the problem appears on all 4.15.0 versions (e.g., 4.15.0-13), but
is not present on any 4.13.0 version (e.g., 4.13.0-45).
The version of Xen used is 4.9.0-0ubuntu3. I believe this isn't in
Xenial's repositories, but actually from a later Ubuntu release, since
I wanted some features of Xen that weren't in Xenial's version.
Bisecting the commits narrowed down to the issue appearing after
http://kernel.ubuntu.com/git/ubuntu/ubuntu-xenial.git/commit/?h=hwe-
edge&id=a62a7117d91ca83d319566cbe16039f4e9f413c2 was committed.
In fact, after recompiling and running the latest hwe-edge kernel
(4.15.0-23) with that commit reverted, the problem disappears. This
kernel is attached.
I also intend to test the mainline kernel, but I haven't gotten around
to it yet
3/4) What you expected to happen/What happened instead
The newer kernel to not be significantly slower than the older kernel (I'm
aware of Meltdown/Spectre mitigations causing slowdowns, but it should not be
*this* much slower).
Specifically, after upgrading to a 4.15.0 kernel from 4.13.0, I noticed these
behaviours:
- Time to log in via lightdm seems to have doubled in time or more (I did not
actually time it, but it is taking significantly longer)
- Scrolling in the Processes tab of system-monitor is noticeably choppy and
laggy
- The "user experience" in general seems to be laggy
- Running a game in a Windows domU (with passthrough GPU) resulted in ~25% of
the original FPS
Interestingly, if I boot on bare metal (i.e., without Xen), the
problem does not manifest.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.15.0-22-lowlatency 4.15.0-22.24~16.04.1
ProcVersionSignature: Ubuntu 4.15.0-23.25~16.04.1-lowlatency 4.15.18
Uname: Linux 4.15.0-23-lowlatency x86_64
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
CurrentDesktop: GNOME-Flashback:Unity
Date: Fri Jun 29 21:46:35 2018
SourcePackage: linux-signed-hwe-edge
UpgradeStatus: No upgrade log present (probably fresh install)
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1779305/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : [email protected]
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
