Thanks for the reply. I'll run Apport as soon as I can access the machine again.
Regarding the actual issue, I don't think it is as cut and dry as this being just about rendering alone, as that would imply that the rendering performance was consistently bad. As I wrote, the performance seems fine on a fresh boot and also after restarting gnome-session (once the bug has appeared), which would not be the case if this was down to just rendering. Some kind of memory issue (leak, fragmentation, ...) seems to play a part in order to explain the time component. Also, there is no window preview (which I assume is a small boxed window preview when Alt-Tab-ing) when I have disabled the Coverflow plugin, yet the stuttering performance was very much present. When it comes to testing out the issue with 19.04, you'll have to bear with me, as this issue takes some time to materialize :-) I have not been able to reproduce it in a short time. Are there any debugging tools I can employ to gain some insight/stats/vitals if/when I encounter this issue? -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1817620 Title: High cpu usage on alt-tab-ing Status in gnome-shell package in Ubuntu: Incomplete Status in mutter package in Ubuntu: Incomplete Bug description: Switching between apps was feeling extremely laggy and unsmooth after some days of keeping the laptop on and just alt-tab-ing between apps would keep the cpu consistently at 100% when hitting it more than 8-9 times per second and *not* letting go of Alt (meaning I stay at the same app). Also, just whizzing the mouse around on the screen (not moving anything) would keep the cpu at 40-50%. Some investigation (1) led me to try out restarting the gnome-shell instance (killall followed by manually starting it in the terminal), upon which everything seemed zippy again. No lagginess. The restart was a supposed fix for a memory leak bug (2), but according to the comments a bug fix was supposed to have landed in 18.04 long ago. So either this has not been fixed or this bug is about something else - probably the latter, as the reported memory usage in htop was nowhere near the gigabytes of memory reported in the bug issue for 16722297. Another thing worth mentioning perhaps, based on comments in (3) found through (4), is that I have disabled all extensions. I used to use the Coverflow extension. Expected behaviour: There should be no percieved lag or stuttering in the interface when switching between applications. Actual behaviour: Switching between applications causes a noticable lag/stuttering when the computer has been running for an extended period of time (weeks, but where it has mostly been suspended, meaning actual usage is limited to 3-4 days). 1. https://www.omgubuntu.co.uk/2018/03/gnome-shell-has-a-memory-leak-and-it-might-not-be-fixed-for-ubuntu-18-04-lts 2. https://bugs.launchpad.net/gnome-shell/+bug/1672297 3. https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1773959 4. https://askubuntu.com/a/1090987/165026 System info: ------------ Running Wayland. Description: Ubuntu 18.04.1 LTS Release: 18.04 gnome-shell: Installert: 3.28.3-0ubuntu0.18.04.4 Kandidat: 3.28.3-0ubuntu0.18.04.4 Versjonstabell: *** 3.28.3-0ubuntu0.18.04.4 500 500 http://no.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages 100 /var/lib/dpkg/status 3.28.1-0ubuntu2 500 500 http://no.archive.ubuntu.com/ubuntu bionic/main amd64 Packages To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1817620/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
