Public bug reported:
Binary package hint: xserver-xorg-video-ati
There is performance problems when enabling EXA (compared to XAA):
- firefox resize, redraw etc (anything that happens to make ff redraw a lot)
- Some windows applications that are using gdi to draw some custom UI.
I made some oprofile testing to locate problems with exa accerlation. I
found that in some applications about 70% of cpu time was used in memcpy
that was called from exaDoMigration->exaDoMoveOutPixmap->exaCopyDirty. I
played a bit with migration settings in xorg.conf and I found that smart
gives the best response times to user input but smart has higher cpu
usage.
Fix for performance problem is setting default MigrationHeuristic to
smart for ati/radeon driver. I don't know any possible problems that
could caused if default is changed to smart. I'm currently testing it in
my system and nothing that I have found so far in 2 hours testing. Of
course choosing Heuristics requires more testing but I think this change
is worth testing and adding to Jaunty (if rumors are true that EXA will
be enabled by default then).
system:
Ubuntu 8.10 all updates installed (including kernel updates).
acer acpire 1359 laptop:
Athlon XP-M
Mobility Radeon 9200 (agp; rv280)
I have manually enabled exa, AccelDFS, DynamicClocks and composite in
xorg.conf.
** Affects: xserver-xorg-video-ati (Ubuntu)
Importance: Undecided
Status: New
--
xserver-video-ati defaults MigrationHeuristic to always. Smart and greedy would
give vissible improvement to performance.
https://bugs.launchpad.net/bugs/330545
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
