On Thu, February 14, 2013 11:09 am, Gene Heskett wrote: > On Thursday 14 February 2013 13:35:26 Ralf Mardorf did opine: > >> On Thu, 2013-02-14 at 12:06 -0500, Gene Heskett wrote: >> > 5 microsecond base thread jitter in its timing >> >> I agree that the nvidia driver could cause issues, but 5 ms jitter? This >> perhaps is an issue for the RTAI, but I guess not for the audio RT >> kernels. >> > Possibly not. What I am pointing out is that unlike all the fussing about > it, xruns and all, and invoking all sorts of black magic speels to control > it, working virtually blind, on LAU/LAD, we were forced to write test > utilities that quantified the results in an easy to understand format. > The > net result being that we have a pretty good idea of the causes of the > failures when the figures do blow up. > > Certain motherboards are pure junk, and a few are truly outstanding given > their relatively meager specs on the box they ship in. The intel Atom > dual > core boards being a case in point. The now almost out of the pipeline > D525MW board, with a gig of ram and onboard intel video being an excellent > example, turning in results consistently under 7 microseconds for a > base_thread jitter when running the base IO thread at a 25 microsecond Have you tested hyperthreading enabled or not? I was quite surprised at the difference on my old P4 as I was able to run my Audio IF at half the latency (32frames instead of 64) with hyperthreading disabled. I have yet to try my atom based netbook this way. I guess linux thinks they are two cores and so is not picky about what it pairs with rt thread, which can end up waiting for CPU time. -- Len Ovens www.OvenWerks.net _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
