| 2020-10-09 15:02:08 |
Radon Rosborough |
description |
On a fresh installation of Ubuntu 20.04 with no configuration files changed yet (the "install third-party software" option enabled), installed from the official daily ISO, the system freezes for about a second every 5-10 seconds and I see a spike to 70% or more CPU usage by gnome-shell. I cannot see anything that shows up in `sudo journalctl -ef` or `sudo dmesg -w` when the freezes occur. The problem reproduces on both X11 and Wayland, although under Wayland it's more annoying since a freeze leads to repeated keypresses of whatever key was being held down on the keyboard at the time of the freeze.
I tried to follow <https://superuser.com/q/1046603> to figure out what was going on with gnome-shell, but I don't think the results seem very helpful.
Result of `sudo perf top`:
4.39% libglib-2.0.so.0.6400.3 [.] g_variant_serialised_n_children
4.26% libc-2.31.so [.] __vfprintf_internal
And `sudo perf top --sort comm,dso`:
45.28% gnome-shell libglib-2.0.so.0.6400.3
17.23% gnome-shell libc-2.31.so
And `sudo perf record -g -p PID` for the `gnome-shell` PID:
+ 39.81% 0.01% [unknown] [.] 0000000000000000
+ 14.26% 2.04% libc-2.31.so [.] __vasprintf_internal
+ 8.61% 8.42% libglib-2.0.so.0.6400.3 [.] g_variant_serialised_n_children
+ 8.51% 8.09% libc-2.31.so [.] __vfprintf_internal
And `strace -c -p PID`:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
34.41 0.128602 5 22784 19837 recvmsg
25.74 0.096215 7 13716 632 ioctl
18.04 0.067420 10 6686 poll
9.50 0.035523 7 4858 write
4.56 0.017025 7 2322 writev
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.4-1ubuntu1~20.04.2
ProcVersionSignature: Ubuntu 5.4.0-49.53-generic 5.4.65
Uname: Linux 5.4.0-49-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.10
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 9 07:54:43 2020
DisplayManager: gdm3
InstallationDate: Installed on 2020-10-09 (0 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20201007)
ProcEnviron:
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/usr/bin/zsh
RelatedPackageVersions: mutter-common 3.36.6-1ubuntu0.20.04.2
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install) |
On a fresh installation of Ubuntu 20.04 with no configuration files changed yet (the "install third-party software" option enabled), installed from the official daily ISO, the system freezes for about a second every 5-10 seconds and I see a spike to 70% or more CPU usage by gnome-shell. I cannot see anything that shows up in `sudo journalctl -ef` or `sudo dmesg -w` when the freezes occur. The problem reproduces on both X11 and Wayland, although under Wayland it's more annoying since a freeze leads to repeated keypresses of whatever key was being held down on the keyboard at the time of the freeze.
This problem seems to have been reported at <https://www.reddit.com/r/pop_os/comments/gwfn7l/gnome_shell_random_cpu_spikes_every_10_seconds/> but with no plausible resolution or workaround in sight.
I tried to follow <https://superuser.com/q/1046603> to figure out what was going on with gnome-shell, but I don't think the results seem very helpful.
Result of `sudo perf top`:
4.39% libglib-2.0.so.0.6400.3 [.] g_variant_serialised_n_children
4.26% libc-2.31.so [.] __vfprintf_internal
And `sudo perf top --sort comm,dso`:
45.28% gnome-shell libglib-2.0.so.0.6400.3
17.23% gnome-shell libc-2.31.so
And `sudo perf record -g -p PID` for the `gnome-shell` PID:
+ 39.81% 0.01% [unknown] [.] 0000000000000000
+ 14.26% 2.04% libc-2.31.so [.] __vasprintf_internal
+ 8.61% 8.42% libglib-2.0.so.0.6400.3 [.] g_variant_serialised_n_children
+ 8.51% 8.09% libc-2.31.so [.] __vfprintf_internal
And `strace -c -p PID`:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
34.41 0.128602 5 22784 19837 recvmsg
25.74 0.096215 7 13716 632 ioctl
18.04 0.067420 10 6686 poll
9.50 0.035523 7 4858 write
4.56 0.017025 7 2322 writev
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.4-1ubuntu1~20.04.2
ProcVersionSignature: Ubuntu 5.4.0-49.53-generic 5.4.65
Uname: Linux 5.4.0-49-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.10
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 9 07:54:43 2020
DisplayManager: gdm3
InstallationDate: Installed on 2020-10-09 (0 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20201007)
ProcEnviron:
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/usr/bin/zsh
RelatedPackageVersions: mutter-common 3.36.6-1ubuntu0.20.04.2
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install) |
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