On Tue, 2009-04-21 at 23:57 +0800, Michael Clark wrote: > Michel Dänzer wrote: > > On Sat, 2009-04-18 at 13:46 +0800, Michael Clark wrote: > > > >> I have made a port of gears that uses the OpenGL ES 1.1 Common API > >> subset (using glDrawElements instead of display lists and optionally > >> using vertex buffer objects). It should be visually equivalent to > >> gears.c, although the flat faces are rendered with GL_SMOOTH to avoid > >> additional draw calls. > >> > >> While testing it, I noticed a severe screen corruption issue when using > >> vertex buffer objects with the intel driver in ubuntu (both ubuntu 9.04 > >> driver and ubuntu xorg-edgers 2.6.99.1+git20090416). I have verified the > >> code is working with the nvidia-180 proprietary driver on another system > >> so I believe it is an intel driver issue. I am wondering if the same > >> issue exists upstream... > >> > >> The attached gearsvbo.c source code can be compiled with: > >> > >> gcc gearsvbo.c -o gearsvbo -lGL -lglut > >> > >> It can be run with or without vertex buffer objects (add -novbo command > >> line option to disable). > >> > >> With the Intel driver I see a 40% speedup with glDrawElements alone. > >> With vertex buffer objects enabled I see almost 200% speedup although > >> the front-buffer doesn't appear to being cleared or swapped correctly > >> (see attached png). > >> > > > > Fixed in Git. > > > > Thanks. I just noticed the fix has arrived in ubuntu xorg-edgers as of > mesa_7.4.1~git20090420+mesa-7-4-branch. > > Before trying this I built from mesa master earlier today and noticed a > performance regression with the 965GM on one of my GL apps - going from > 15fps to 7.5fps (both running on top of latest drm-intel 2.6.30-rc2). > 7.4.1 doesn't exhibit the slow down. > > It seemed to be a timing issue as the app would no longer be using all > cpu of a single core (noticeably less cpu than on the 7.4-branch > version), and paradoxically, running another cpu intensive task would > result in the fps increasing. I'll do some more testing (and double > check the two builds were configured equivalently)...
bisecting would be the best thing to do if you've got a performance drop and it's not a CPU-bound app. -- Eric Anholt e...@anholt.net eric.anh...@intel.com
signature.asc
Description: This is a digitally signed message part
------------------------------------------------------------------------------ Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p
_______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
