Bug#803351: gnome-shell: high cpu consumption and long time to login

[Drew Parsons]

On Thu, 12 Nov 2015 00:49:46 +0800 Drew Parsons <dparsons at emerall.com>
wrote:
> On Thu, 29 Oct 2015 01:52:50 +0100 gpe92 <gpe92 at free.fr> wrote:
> >
> > Since the update to gnome-shell 3.18 the login takes very long time
> > (more than 1 minute) and after there is a processus 'gnome-shell
> > --mode=gdm' which consumes 20% of CPU all the time.
> 
> ...
> ... high CPU usage by gnome-shell could be caused by extensions.
> 

No, probably not extensions in this case. The clue is "--mode=gdm".

The gnome-shell that you interact with is run under your own user name.
But 'gnome-shell --mode=gdm', the instance with the high CPU usage, is
run under user Debian-+.

The high CPU usage is reported also on Redhat. Apparently it only
happens with the nvidia proprietary video driver.

A workaround is to switch to the virtual terminal on which 
'gnome-shell --mode=gdm' runs, e.g. Ctrl-Alt-F7, then back again.  That
seems to reset the process so it stops spinning the CPU.

cf. https://bugzilla.redhat.com/show_bug.cgi?id=1298935

Fixed in gdm-3.18.2-2.fc23 with a patch managed at 
https://bodhi.fedoraproject.org/updates/FEDORA-2016-6f8f961dc4