Re: [LAU] Ubuntu-Studio 13.04 Nvidia drivers?

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
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