Re: fc2, xorg, 2.6.x, scheduling latency peaks

[Fernando Pablo Lopez-Lezcano <nando ccrma Stanford EDU>]

On Thu, 2004-05-27 at 17:25, Fernando Pablo Lopez-Lezcano wrote:
> Hi all. I'm trying to track the cause of high scheduling latency peaks
> in FC2 that make the system unusable for low latency audio work. 
> 
> Test systems: PIV laptop, radeon video chipset, AMD64 desktop, radeon
> video chipset. How I test: I run the Jack (Jack Audio Connection Kit)
> sound server with 2 or 3 128 frame buffers for low latency operation
> through the Qjackctl gui front-end. I then start GUI apps that use Jack
> (for example Freqtweak, Hydrogen and Jamin). I see plenty of buffer
> xruns of varying durations during the app load process and afterwards.

More data I forgot to include:
Jack is running with SCHED_FIFO priority. For achieving that I run a
custom kernel (currently based on Arjan's 1.391) with preempt enabled
and the realcap kernel module (by Jack O'Quin) added. I also run an up
to date version of ALSA with full debugging enabled so that I can get
kernel stack traces when xruns occur. 

-- Fernando