forgot to cc the list ... forwarding. <div class="gmail_quote">---------- Forwarded message ---------- From: Justin Smith <<a href="mailto:justinsmith2009@gmail.com">justinsmith2009@gmail.com</a>> Date: Thu, Jan 22, 2009 at 4:59 PM Subject: Re: [Xorg-driver-geode] huge difference between hwaccel and no accel performance ?? To: Mart Raudsepp <<a href="mailto:mart.raudsepp@artecdesign.ee">mart.raudsepp@artecdesign.ee</a>> Hi Mart, Thanks for your detailed response. Another followup question I have is how to get the xv maximum image size from 1k x 1k to 2k x 2k. Is there a patch available already? I have found couple of bugs, one in 2.11.0 and one in the last checkin that you have done - what is the best way to report bugs. Thanks, Justin<div><div></div><div class="Wj3C7c"> <div class="gmail_quote">On Wed, Jan 21, 2009 at 4:02 AM, Mart Raudsepp <<a href="mailto:mart.raudsepp@artecdesign.ee" target="_blank">mart.raudsepp@artecdesign.ee</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Ühel kenal päeval, T, 2009-01-20 kell 17:09, kirjutas Justin Smith: <div><div></div><div>> Hi guys, > > I am running some x11perf benchmarks and I see a huge performance > difference in the wrong direction. The no accel option is much faster > than the accelerated option. > Is the "No Accel" flag reversed, meaning "No Accel" is enabling the > acceleration? </div></div>No, it is not reversed. If NoAccel is set, then EXA isn't initialized and the acceleration architecture isn't really used. The most common reason of accelerated being slower than software is when the pixmap migration overhead exceeds the wins of acceleration. I'm not sure this is the case here, but that's what has plagued many EXA using drivers in the past. Do you have any concrete things that are slower and are actually a problem in real life modern applications? Note that it is also quite important to be using a recent xorg-server, as the EXA common code has received many improvements to it that improve the matter in xorg-server-1.4, even more in 1.5 and also more in what will become 1.6 (a RC2 or so should be out). However for information, and a possible call for contributions: One problem with the very latest xorg-server for geode seems to be the glyph cache found in trunk and server-1.6-branch. It is a huge win for many drivers, but it is my belief that its mask generation is causing it to be a major loss for geode at this time. This however needs some further verification. In concrete I have commit 54184110f6f3e5d7276d5431e739a4fcf0c3523e to xserver in mind. It adds a glyph cache and I believe it adds quite some Pict_A8 (alpha channel only) PictOpAdd operations to that hot path, which is currently not accelerated on geode, because the hardware does not have pure alpha pixmap support. A possible solution for that regression would be to make it possible for the driver to instruct the EXA glyph infrastructure to always use ARGB there, so we can accelerate the PictOpAdd composite operations, trading the overhead to four time larger caches (though it seems its also keeping ARGB caches as well anyway?). Another possibility could be to hack together a way to convert A8 to ARGB in the hardware side. Adam Jackson had some ideas in that area, but that could be a complementary to cover the cases where we can't make the pixmaps passed to not be A8 in the first place - probably for other operations than glyph drawing. Once someone fixes that regression, we can reap the benefits of the glyph cache and end up with quicker glyph drawing than without glyph cache in <xorg-server-1.6, as for other drivers. All the other EXA changes in trunk and server-1-6-branch are probably a win, so possibly just glyph drawing would be slower. Note that some distributions have backported the EXA glyph changes and more to their xorg-server-1.5 as well. Gentoo and Fedora come to mind, iirc. Regards, Mart Raudsepp Artec Design LLC _______________________________________________ Xorg-driver-geode mailing list <a href="mailto:Xorg-driver-geode@lists.x.org" target="_blank">Xorg-driver-geode@lists.x.org</a> <a href="http://lists.x.org/mailman/listinfo/xorg-driver-geode" target="_blank">http://lists.x.org/mailman/listinfo/xorg-driver-geode</a> </blockquote></div> </div></div></div>