Awesome info Rob! Can we post this to the website? I will also see about posting an updated kernel in errata that fixes this, but I'm not sure its feasible (breaking Cell/Power5 would not be good).
Cheers, Owen [EMAIL PROTECTED] wrote: > Hello all, > Just wanted to post a few observations about what I've seen with YDL6. My > computer is a dual 2Ghz G5 > PowerMac with the Radeon 9600 graphics card (the beastie with the DVI and the > ADC connectors). I'd > noticed a fairly significant performance hit when moving from YDL4.0.91 to > YDL6 (long story for staying > with 4.0.91 for so long...), on the order of 4x or so *especially* when using > graphics. I've got two > Sceptre X20WG LCD's attached, and YDL6 was the first linux I've been able to > get true 'stable' dual > head graphics on. > Anyway, after going back and forth with some of the kernel developers and > some folks from Xorg I've > gotten rid of most of the performance degradations. The changes were in two > chunks: > > STEP 1 - X11 configuration > My initial Xorg config came from running 'Xorg -configure'. This gave me a > working X11 with > the same display on both monitors. I was able to use > '/usr/bin/system-config-display' (or the > menu equivalent) to change to a multi-head display. Note however that the > display tool > wasn't able to save the new setup *IF* the second monitor was configured as a > 'generic 1680x1050'. > So I set it to 'generic 1280x1024', and then edited /etc/X11/xorg.conf to fix > this. > I also edited /etc/X11/xorg.conf to set "Clone" to "False", and the drivers > to "radeon" instead of "ATI". The > kicker is to *also* set the "AccelMethod" options to "EXA". Seems there is a > bug where XAA (the default) > causes a severe performance hit. > > STEP 2 - kernel configs > My initial suspicions for the slowdown were aimed at the kernel, since I > was seeing problems even when > graphics were not in use. I did these changes *first*, then found out about > the X11 issues above, so I don't > know how much of an effect these mods had, although I did see some > improvement after doing these. > At any rate, I downloaded the 2.6.25-rc8 kernel and rebuild after tweaking > some kernel configs: > 64 bit kernel > processor support -> opt for power4, altivec, SMP (maxcpus=2) > platform support -> machine type (generic), *only* apple powermac for > machines > > > Again, don't know if the kernel rebuild played much of a factor. I saw some > performance gains > after doing the kernel mods, but the real speedup came after tweaking the X11 > setup. > > Hope this might help someone else... I liked YDL6 alot (performance issue > was a growing concern), but life > is much better now..... > > > Rob > _______________________________________________ > yellowdog-general mailing list > [email protected] > http://lists.terrasoftsolutions.com/mailman/listinfo/yellowdog-general > HINT: to Google archives, try '<keywords> site:terrasoftsolutions.com' > _______________________________________________ yellowdog-general mailing list [email protected] http://lists.terrasoftsolutions.com/mailman/listinfo/yellowdog-general HINT: to Google archives, try '<keywords> site:terrasoftsolutions.com'
