On Tue, 28 Apr 2009, Steve Harris wrote:
> I don't know about jitter, but certainly a few years ago, you sometimes got > stalls - eg. under heavy DMA load. That may not be an issue with modern CPUs > and chipsets. I think I posted some code that demonstrated it to the l-a-d > list at the time, but good luck finding it :) > Thanks for the warning. I'm not planning to run other programs or do any I/O besides audio though. And to avoid rescheduling while my code snippets run, I'll probably set the threads to SCHED_FIFO/99 too. Hopefully that'll give accurate results. Paul Davis wrote: > the cycle counter on intel systems is (was?) guaranteed to run exactly > in sync. AMD had a problem a few generations back where they neglected > to provide this feature and it caused havoc for several different > categories of users. they corrected their error very quickly and i > believe that all their chipsets will now also always have precisely > A synced cycle counter. Thanks. > in the absence of frequency scaling, there is no jitter that can be > measured using anything else you're likely to have attached to the > computer. Sorry, really bad use of the word "jitter" on my part. I ment slightly wrong values caused by unsynchronized tsc clocks. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
