[pulseaudio-discuss] Latency vs CPU

Tanu Kaskinen tanuk at iki.fi
Thu Mar 15 20:42:35 PDT 2012

On Mon, 2012-01-30 at 19:34 +0200, Tanu Kaskinen wrote:
> On Mon, 2012-01-30 at 07:12 -0500, Sean McNamara wrote:
> > So my conclusion is that either
> > (A) time-based scheduling isn't implemented for module-null-sink, or
> > (B) there is some bug causing this strange behavior.
> > 
> > In case (A), would it be possible, even in principle, to implement it?
> > In case (B), is this a bug that anyone can look into? Can provide as
> > much additional info as required.
> IIRC, module-null-sink simulates a timer-based sink (due to being a null
> sink, it's timer-based anyway, but I think it tries to act similarly to
> an alsa sink that uses timer-based scheduling). So it looks like case B.
> I can't speak for others, but I probably won't look into this bug myself
> in the near future. If you file a bug, I may investigate this at some
> later time.
> > Maybe there's some other third possibility, but I'm just not expecting
> > this kind of behavior out of PA. I thought all the tsched work was to
> > help to juggle latency-intensive streams simultaneously with
> > high-latency streams without impacting the latter's CPU usage?
> At least when there are no low-latency clients, the latency should
> return to the higher level. I'm not so sure about whether the current
> implementation is supposed to keep the latency high for high-latency
> clients when there are low-latency clients at the same time. I think it
> should be possible to do that, though, even if the current
> implementation doesn't try to achieve that.

I filed a bug about this:


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