每日彙整: 2017-11-03

樹莓派、樹莓派之學習、樹莓派之教育

【鼎革‧革鼎】︰ Raspbian Stretch 《六之 D 》

新舊交接時期終究事多，樹莓派論壇有人談起︰

Mesa driver much slower on Stretch than on Jessie

RichardRussell

Sat Aug 26, 2017 4:32 pm

Running ‘glxgears -info’ on Raspbian Jessie is reporting around 180 frames-per-second rendering speed but the same on Stretch is reporting only about 45 FPS, or a quarter of the speed! This is on the same hardware (a Raspberry Pi 3 with HDMI output), in both cases with the ‘experimental’ VC4 GL Driver disabled.

Another oddity is that when running on Jessie the gears are blue, red and green but on Stretch they’re white, yellow and cyan! I suppose this could be a deliberate change but it seems suspicious. The Mesa versions are reporting as 13.0.0 and 13.0.6 respectively.

Can anybody suggest what’s going on here? When it’s possible to enable the ‘experimental’ GL Driver there’s no noticeable difference in performance, but when it’s disabled Stretch can be unusably slow when Jessie was acceptable.

Richard.

 

驗之，真的也︰

 

 

 

pi@raspberrypi:~ glxinfo | grep -i opengl libGL error: failed to open drm device: No such file or directory libGL error: failed to load driver: i965 OpenGL vendor string: VMware, Inc. OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.9, 128 bits) OpenGL core profile version string: 3.3 (Core Profile) Mesa 13.0.6 OpenGL core profile shading language version string: 3.30 OpenGL core profile context flags: (none) OpenGL core profile profile mask: core profile OpenGL core profile extensions: OpenGL version string: 3.0 Mesa 13.0.6 OpenGL shading language version string: 1.30 OpenGL context flags: (none) OpenGL extensions: OpenGL ES profile version string: OpenGL ES 3.0 Mesa 13.0.6 OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00 OpenGL ES profile extensions: pi@raspberrypi:~

 

GitHub 上有人建議︰

OpenGL performance reduced on Raspbian Stretch #79

XECDesign commented on Sep 4

After a bit of testing, it does look like this is an issue which affects software OpenGL rendering in general, not just glxgears. However, the change of behaviour comes from upstream Debian packages and software opengl rendering is not something we’ve ever touched or claimed to support. I would recommend enabling vc4 fkms in raspi-config for proper OpenGL support.

 

證之，果然矣︰

 

 

 

pi@raspberrypi:~ glxinfo | grep -i opengl libGL error: failed to authenticate magic 3 libGL error: failed to load driver: i965 OpenGL vendor string: VMware, Inc. OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.9, 128 bits) OpenGL core profile version string: 3.3 (Core Profile) Mesa 13.0.6 OpenGL core profile shading language version string: 3.30 OpenGL core profile context flags: (none) OpenGL core profile profile mask: core profile OpenGL core profile extensions: OpenGL version string: 3.0 Mesa 13.0.6 OpenGL shading language version string: 1.30 OpenGL context flags: (none) OpenGL extensions: OpenGL ES profile version string: OpenGL ES 3.0 Mesa 13.0.6 OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00 OpenGL ES profile extensions: pi@raspberrypi:~

 

然而目前樹莓派 G1 GL

 

還很挑 HDMI 顯示器才開機哩！故置疑焉？