[PD] Gem performance tests?
derek at x-i.net
Tue Apr 19 22:10:25 CEST 2005
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
derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 56:
"Do the washing up"
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