Patterned slow-down over the entire GNOME desktop

[Ivan Gyurdiev]

Nicolas Mailhot wrote:
> darrell pfeifer wrote:
>> I have a two year old laptop that uses the radeon driver.
>>
>> The last few kernels from rawhide left a really sluggish response.
>> Switching between virtual screens gave a really noticeable repaint. I
>> also had the feeling that I/O in general was very slow.
>>
>> The latest 1806 kernel is much better, so this might not be an X 
>> problem.
>
> My feeling was more some sort of scheduler problem, with apps being 
> randomly starved. As long as you stayed in the same app everything was 
> very fast, trying to switch or launch a new app would either be 
> reasonably fast of slow as hell. Starvation was not linked to any 
> particular app, more (like Ivan noted) to launch ordering.
>
> I never noticed any particular load peak that could explain the 
> slowdowns. And this box had 256 MB which is not bad for its generation 
> and the only reason it can still be used.
But see...those are all GUI apps. More specifically, they're all gtk apps.
Correct me if I'm wrong, but wouldn't a kernel issue affect all apps on 
the system - it doesn't appear that way to me. Also, I don't know if 
this is relevant, but if you compare `strace -c` on a fast and slow run, 
they look almost exactly the same syscall distribution, and cover a very 
small amount of total time (1 sec).

I was particularly interested in bittorrent, as a simple test case - 
doesn't it only link to gtk2 over pygtk2? We know python isn't the 
issue, since C apps are slow too.

However... this is interesting. I observe no slowdown as root - all the 
apps start reasonably fast. Can you confirm this? Also, I see that there 
have been no significant changes in gtk2 lately, while I know that this 
bug must have been caused by upgrades in the last two weeks or so.

Hmmm...