[linux-audio-user] Shaving CPU cycles

Ken Restivo ken at restivo.org
Fri Feb 2 23:32:00 EST 2007


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On Wed, Jan 31, 2007 at 10:52:50PM -0500, Ross Vandegrift wrote:
> On Wed, Jan 31, 2007 at 02:25:26AM -0800, Ken Restivo wrote:
> > 2) Try DRM or some kind of accelerated graphics for Xorg
> 
> This might make the problem worse.  Many graphics cards are mean to the
> PCI bus.  The extra interrupts can make latency issues worse.
> 
> What version of fftw is being used on your system?  If you're using
> fftw v2, make sure to build it for your arch!  If you're using fftw3,
> arch specific SIMD is automatically used by the lib.
> 

Speaking of making the problem worse, using the p4fftwgel2 package, which is optimized for P4, makes CPU usage *higher*. I'm not even kidding.

But, and even more strangely, it seems to also makes the crackling a little better, even though CPU usage is higher. It's as if it allows the CPU usage to go to higher levels before failure, but itself takes up more CPU.

I'm completely baffled as to why this is.

- -ken
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