Messages in this thread |  | | | Date | Mon, 30 May 2005 12:33:47 +0200 | | From | Ingo Molnar <> | | Subject | Re: RT patch acceptance |
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* Andi Kleen <ak@muc.de> wrote:
> > Yes, as Ingo stated many times, addition cond_resched() to > > might_sleep() does achieve the "usable" latencies -- and obviously > > that's hacky. > > But it's the only way to get practial(1)low latency benefit to > everybody - not just a few selected few who know how to set the right > kernel options or do other incarnations and willfully give up > performance and stability. > > It is basically similar to why we often avoid kernel tunables - the > kernel must work well out of the box. > > (1) = not necessarily provable, but good enough at least for jack > et.al.
FYI, to get good latencies for jack you currently need the -RT tree and CONFIG_PREEMPT. (see Lee Revell's and Rui Nuno Capela's extensive tests)
In other words, cond_resched() in might_sleep() (PREEMPT_VOLUNTARY, which i announced Jul 9 last year) is _not_ good enough for advanced-audio (jack) users. PREEMPT_VOLUNTARY is mostly good enough for simple audio playback / gaming.
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