[Mesa3d-users] Strange framerate for direct vs. indirect rendering

[Philipp K. K. <pk...@sp...>]

Disclaimer: I know glxgears is not a benchmark, and I'm asking this
question out of curiosity, not out of some attempt to benchmarkusing
glxgears.

Why do I consistently get higher glxgears framerates with indirect
rendering? Here's some glxgears output:

1736 frames in 5.0 seconds = 347.084 FPS
1676 frames in 5.0 seconds = 335.017 FPS
1500 frames in 5.0 seconds = 299.872 FPS
1651 frames in 5.0 seconds = 330.194 FPS
1741 frames in 5.0 seconds = 347.826 FPS
1542 frames in 5.0 seconds = 308.269 FPS
1544 frames in 5.0 seconds = 308.688 FPS
^C
philipp@notebook3:~$ export LIBGL_ALWAYS_INDIRECT=1
philipp@notebook3:~$ glxgears
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
2241 frames in 5.0 seconds = 446.507 FPS
2020 frames in 5.0 seconds = 401.752 FPS
2340 frames in 5.0 seconds = 463.619 FPS
2120 frames in 5.0 seconds = 420.840 FPS

System info:
OpenGL vendor string: Tungsten Graphics, Inc
OpenGL renderer string: Mesa DRI Intel(R) 965GM GEM 20091221 2009Q4
OpenGL version string: 1.4 (2.1 Mesa 7.7.1)

Philipp