Messages in this thread | | | Subject | Re: v2.6.19-rt6, yum/rpm | From | Arjan van de Ven <> | Date | Thu, 07 Dec 2006 22:20:45 +0100 |
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On Thu, 2006-12-07 at 21:58 +0100, Ingo Molnar wrote: > * Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU> wrote: > > > Much better performance in terms of xruns with Jackd. Hardly any at > > all as it should be. I'm starting to test -rt8 right now. > > > > Now, I still don't have an smp machine to test so the improvement > > could be because I'm just running 64 bit up instead of smp. Or it > > could have been the hardware on that other machine that had some > > problem (either because it was starting to fail or because the kernel > > drivers for that hardware were somehow triggering the xruns). > > i think it's the UP vs. SMP difference. We are chasing some SMP > latencies right now that trigger on boxes that have deeper C sleep > states. idle=poll seems to work around those problems.
well C-states do cause latencies... as advertized in the /proc/acpi/processor/CPU0/power file.
You can prevent linux from going into c-states that just take too long, by setting the latency you can tolerate via the set_acceptable_latency(). You can see the active maximum latency via the same power file...
(right now audio playback is the main user of this api; of other parts should use it too lets talk about it)
-- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org
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