Hi Mike,

Mike Wozniewski wrote:

• Differences between Linux kernels - particularly compared with the

optimized PlanetCCRMA kernel.

• The benefit of the -rt (realtime performance) option.

I'm afraid that the CCRMA kernel probably doesn't give you much of an edge over any other kernel in this case. Neither would -rt AFAIK. All of this has to do with audio optimizations, which is pretty moot for GEM unless you are doing audio with it. My understanding is that OpenGL is working primarily in the hardware, so the dataflow in PD which sends instructions to the GEM objects (which then send instructions to the video card) probably isn't chewing up so much resources that low-latency or preemptive kernel patches will make a noticable difference.

So what will give you an edge would be good video drivers with properly configured OpenGL support. For NVidia and Radeon cards, for example, often the "best" drivers (in terms of performance) are still the closed-source, non-free drivers released by the manufacturers. The X11 drivers and other free + open source ones seem noticably slower.

I'm not sure what drivers are included in CCRMA, but I'd bet that they are not compiled into the kernel, but are rather external modules if you have a dedicated graphics card. RedHat/Fedora, SuSE and others most often use the non-free binary drivers, while Debian, Gentoo and similar users choose at install time the free or non-free options.

My experience is that NVidia hardware with non-free drivers seems to work better for OpenGL than Radeon with any drivers on Linux, but for some this is the devil's road ;-) If others on the list have had better luck with the the free video drivers, please speak up. I'd be curious to know.

derek