https://bugs.freedesktop.org/show_bug.cgi?id=38800
Summary: glXSwapBuffersMscOML is slow on AMD Fusion but not on Intel 945 w/Atom Product: Mesa Version: unspecified Platform: x86 (IA32) OS/Version: Linux (All) Status: NEW Severity: normal Priority: medium Component: Drivers/Gallium/r600 AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: simon.farnsworth@onelan.co.uk
Created an attachment (id=48588) --> (https://bugs.freedesktop.org/attachment.cgi?id=48588) My test program to demonstrate the performance issues
I'm trying to get an in-house OpenGL compositor up to the same performance on AMD Fusion as it currently achieves on Intel graphics, and I've found that glXSwapBuffersMscOML is slower (with a trivial test program) on AMD than it is on Intel.
I've attached my test program (swapbufferstest.c), which I've been compiling with:
gcc -O2 -ggdb -Wall -Werror -o swapbufferstest swapbufferstest.c -lX11 -lGL -lGLEW -lGLU
I'm running identical Fedora 15 based software stacks on an Intel Atom D510 (integrated GMA 950 class graphics) and on an AMD Fusion board (GPU PCI ID [1002:9802]).
On Intel, I get output like: # ./swapbufferstest Screen is 1920x1200 Longest frame time 17.308969 ms Biggest delta 3 frames, averaging 1.034188 frames per swap Average swap interval 17.118282 ms 121 frames, 117 swaps
On AMD, I get: # ./swapbufferstest Screen is 1920x1200 Longest frame time 16.751312 ms Biggest delta 3 frames, averaging 3.000000 frames per swap Average swap interval 49.326561 ms 123 frames, 41 swaps
I've confirmed that I've got a direct rendering context in both cases; on Intel, I've been able to confirm that I'm doing page-flipping, but I can't yet work out how to do that on the AMD driver; however, only hitting one frame in 3 doesn't seem right to me, especially since it's not reaching 10% CPU load. I can't however see whether I'm actually hitting the pageflip codepath, or whether I'm in a slow path.
Versions of interesting components are:
kernel-PAE-2.6.38.8-91.fc15.i686 mesa-dri-drivers-7.11-0.11.20110525.0.fc15.i686 libdrm-2.4.26-1.fc15.i686 xorg-x11-server-Xorg-1.10.2-1.fc15.i686 xorg-x11-drv-ati-6.14.1-1.20110504gita6d2dba6.fc15.i686 xorg-x11-drv-intel-2.15.0-3.fc15.i686
I'm able to rebuild RPMs with extra patches if needed for testing, and I have both systems to hand for testing as needed.
I'll attach dmesg and Xorg.log from the AMD system to this bug.