I would like to propose re-enabling "greedy" migration as a solution to performance issues with -intel. PPA for testing is available at:
http://people.ubuntu.com/~bryce/Testing/intel-bug359600/ Please test and let me know if you spot any regressions from Intrepid caused by this package. [Discussion] One of the last[1] remaining big issues with the -intel driver for Jaunty are performance problems that a number of people are seeing on their hardware. Back in Hardy when we were also seeing performance issues, I included a patch[2] that set the "greedy" migration heuristic on by default when using EXA. In preliminary testing, we find this option is helping in this case as well. It seems to provide approximately the same performance benefits that the "UXA" option provides, but without the stability problems people have seen. What the patch does is refuse to let go of certain pixmaps, preventing various acceleration algorithms from being run. Obviously, upstream would prefer to see these new algorithms used rather than bypassed, so they do not recommend using this options[3]. However, in situations where those algorithms are not working right, this can actually improve performance as it prevents the overhead of migrating the pixmaps around. So, this is a horribly ugly workaround, but hey, if it works... What I'm concerned with is crash bugs that occur with this patch enabled, that were not present in Intrepid. In particular, I'm concerned about bug #246581 rearing its head again[4]. Please bring such issues to my attention ASAP. Rumors suggest that greedy may also cause some graphics corruption issues. As long as they're minor annoyances and don't prevent usage of the machine, these may be an acceptable price to pay, but let me know. Please test the debs here[5]: http://people.ubuntu.com/~bryce/Testing/intel-bug359600/ Let me know of any regressions from Intrepid that this causes. Bryce 1: There are also some inexplicable X freezes seen esp. when running with compiz that we are working on. Current theory is a regression in the mesa 7.3->7.4 upgrade, since downgrading to 7.3 seems to help (but hasn't resolved all freeze issues so we're not 100% sure). 2: http://launchpadlibrarian.net/25354124/05_intel_exa_force_greedy.patch 3: http://lists.freedesktop.org/archives/xorg/2008-May/035459.html (Esp. see follow up posts where it is suggested the option is not inappropriate to be carried at the distro level.) 4: https://bugs.edge.launchpad.net/ubuntu/+bug/246581 -- Ubuntu-x mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-x
