Patterned slow-down over the entire GNOME desktop

[Dennis Jacobfeuerborn]

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.

All of this *might* to a problem I reported on the xorg mailinglist last 
month. I also noticed quite sluggish performance so I ran oprofile and 
noticed that xorg calls fbcopyareammx quite a lot which results in two 
things: a) "sluggish"-looking drawing performance because of the cpu is 
used where the on-board blitter should be and b) spikes in cpu utilization 
because of a). Alan Coopersmith apparently found some problem with xorgs 
memory allocation which seems to push all pixmaps into host memory instead 
of the on-card memory which causes at least the radeon driver to hit a lot 
of cpu fallbacks and people with a fast cpu will obviously will see less of 
an impact. Eric Anholt is doing some memory manager work right now which 
hopefully fixes that issue.


Regards,
   Dennis