[PD] Pd 20% idle CPU usage on MBP

[brandon zeeb]

Great detective work!  I'd love to see better CPU performance on OS X.
Hopefully this also implies that one could see their Pd->Jack performance
increase as well.

Cheers,
~Brandon

On Mon, Nov 1, 2010 at 7:31 AM, Jamie Bullock <jamie at postlude.co.uk> wrote:

>
> On 28 Oct 2010, at 17:55, Mathieu Bouchard wrote:
>
> > On Thu, 28 Oct 2010, brandon zeeb wrote:
> >
> >> This thread comes up every year or two,
> >
> > I'd say at least twice a year... I think I already wrote about it on
> pd-list this autumn, no...? But it's hard to search the archives about the
> frequency of that thread, as the keywords might not be consistent. I just
> know that the problem has existed for quite a few years and that I read
> about it on pd-list more than a handful of times.
>
> Indeed! I remembered it coming up and so I searched the archives before
> posting, but keywords like 'cpu' and 'usage' don't do very much.
>
> However, digging a little with Shark, I see that a high proportion of Pd's
> CPU time is spent talking with the audio hardware, so I try Google: "
> DspFuncLib portaudio", and lo and behold:
>
>        http://www.google.co.uk/search?q=DspFuncLib+portaudio
>
> Trouble is "use jack" doesn't solve the problem, it merely avoids it.
>
> So, zooming in a bit, I see at least two issues here:
>
>        1. there is a lot of activity in the underlying audio drivers when
> using the Portaudio driver on OS X, even when audio is off in the
> application.  Let's call this the 'idle' CPU usage. IMO, this should be less
> than 1% on modern CPUs for well behaved applications. I've added this to the
> bug tracker.
>
>        2. there is a lot of activity in the underlying audio drivers when
> using the Portaudio driver on OS X, when audio is on in Pd. Comparison with
> AudioMulch, which also uses Portaudio suggests that is only in part a
> Portaudio problem. AudioMulch idles at ~10% on my machine. I suspect that
> the problem with Pd+portaudio may be due to a small buffer size used by Pd.
> I thought Pd's 'Delay' setting in audio preferences was supposed to handle
> this, but changing delay to 500ms, has no effect on CPU use. Also added to
> tracker.
>
> Jamie
>
>
>
>
>
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