ubuntu-x-swat team mailing list archive

[Pauli <suokkos@xxxxxxxxx>]

On Wed, May 13, 2009 at 11:25 AM, Bryce Harrington
<bryce@xxxxxxxxxxxxxxxxxxx> wrote:
> We messed around a bunch with different migration heuristic options with
> the intel driver.  Certainly there were some measurable improvements
> when using greedy, however it was found to cause graphics corruption on
> some systems (indeed, corruption issues are to be expected by design
> with greedy).
>
> As I understand it, all these performance issues are part and parcel of
> iniquities in DRI1/EXA design, and so in theory DRI2 should solve them.
> I'm not sure when we can expect DRI2 for -ati, but it's already
> available for -intel so I expect it should be arriving soon, hopefully
> in the Karmic time frame.
>
> Hopefully this explains why I don't think we need to pursue greedy for
> ati.
>

Radeon drm module didn't make it to 2.6.30 kernel which means that
Karmic won't have dri2 for radeon cards unless there is plan to use
2.6.31 or backport the changes from Fedora.

Maybe it would be good idea to have gui option to select migration
heuristic because it gives clear boost for system where bandwidth to
graphics card is very limiting factor (like older radeon cards)

I haven't at least seen or heard about corruption with radeons if
changing heuristics. Most often cause is accelerated download from
screen extension.

Anyway. I think "smart" is the better option than "greedy" if wanting
to get the least lag for the UI.

-- 
xserver-video-ati defaults MigrationHeuristic to always. Smart and greedy would give vissible improvement to performance.
https://bugs.launchpad.net/bugs/330545
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