[PD] switch~ & cputime climbing

[Dafydd Hughes]

Hi folks

Okay - I think this is more or less the same patch, with a couple of
minor changes:

http://sideshowmedia.ca/cputest.zip

Oddly, I can't reproduce my original problem, although some
fascinating new things have shown up.  Perhaps it was a PowerPC issue?
 (I'm now on a MacBook)

Try switching on & off the main dsp and test_lois.  On my computer
(extended test 6 - delays not working in later tests) cputime goes up
slightly when I turn dsp off.

I never figured out exactly why the climb was happening, but I found
that it happened when I turned off dsp in the abstraction, but left
the non-dsp elements running, ie continually trying to pass messages
to line~ and vd~ objects etc.  Switching off the mechanics when
switching off dsp solved it for me.

I hope this helps!  I'd love to hear if this test patch climbs on a
PowerPC still.

cheers
dafydd

On 6/6/07, Phil Stone <pkstone at ucdavis.edu> wrote:
> Hi Derek,
>
> I'm not positive about this, but I think I've traced the CPU-climb to
> the [moog~] filter.  It has an odd behavior that can be broken into
> three phases:
>
> 1) no audio greater than zero amplitude has passed through it yet (since
> patch load)
> 2) audio of some amplitude >0 passes through
> 3) audio passing through goes back to zero amplitude
>
> At 3) (or, more accurately, several seconds after), its CPU usage climbs
> fairly dramatically, only to drop down again when the amplitude of the
> audio goes up again.   Something in the filter model doesn't like zero
> amplitude, but only after it's first processed something greater than zero.
>
> I meant to test this more rigorously, but got sidetracked.  At any rate,
> when I switch~ the [moog~] filter out, CPU usage holds steady.  To be
> clear, I don't think this relates to [switch~].  I'm on a Macbook Pro,
> currently running 0.39rc2.
>
> Phil
>
>
>
> Derek Holzer wrote:
> > Hi Phil,
> >
> > just to keep this in people's minds... I have exact same problem
> > described in these emails with my Particle Chamber granular synthesis
> > patch. It has 32 "switch~ed" voices. Using one instance seems to be
> > OK, but two or more leads to exponentially-growing CPU usage that
> > eventually makes PD unresponsive to the GUI (and eventually would
> > probably crash PD if I let it go on...) I guess this could relate to
> > the "isn't the GUI supposed to have lower priority than    process?"
> > thread, since this particular problem makes PD a bit unusable for the
> > kind of performances I want to be doing with it. The fact that PD
> > lacks a usable voice-allocation method (i.e. CPU resources can be
> > allocated and de-allocated to a voice, something which switch~ has a
> > bug with, and which Nqpoly~ and so on does not do at all) means that I
> > must start looking into SuperCollider to work with my polyphonic
> > granular synthesis stuff. Sad but true...
> >
> > d.
> >
> > Phil Stone wrote:
> >> Hi,
> >>
> >> I'm getting a slow-but-steady climbing CPU when running some
> >> synthesis patches.  I (like the poster below) have sub-modules that
> >> can be switch~ed on and off.  An archive search turned up the
> >> following un-replied post:
> >>> Hi all
> >>>
> >>> Okay.  I'm stumped.
> >>>
> >>> Recently, I've noticed that my cpu meter has been steadily rising.
> >>> I  think I may have found the culprit.
> >>>
> >>> A while back I thought I'd put a power switch (just a switch~
> >>> object)  on my poor-man's granular delay line, as my performance
> >>> patches are  getting a bit bulky.
> >>>
> >>> Try this (if you have the time):
> >>>
> >>> http://www.sideshowmedia.ca/cputest.zip
> >>>
> >>> cputest.pd: (needs expr, but I think that's all)
> >>>
> >>> 1. turn on audio in pd, but leave the power (p toggle) in "lois"
> >>> off.  Watch the cpu meter climb (over a period of 5 minutes or so -
> >>> the toggle prints the cputime every 10 seconds).  On my computer
> >>> (G4  Powerbook, HCS extended 0.38.4) it starts around 5% and hits
> >>> 10%  after 5 minutes.
> >>>
> >>> 2. Do the same with "lois" on.  For me, cpu hovers around 13-14%.
> >>> No  increase.
> >>>
> >>> 3. Repeat step 1.  After 10-15 minutes, cputime is higher than with
> >>> "lois" on.  Switch "lois" on, and cpu drops.  Huh?
> >>>
> >>> I have no idea what's going on, but am I missing something
> >>> important?  Thanks in advance.
> >>>
> >>> cheers
> >>> dafydd
> >>>
> >>
> >> Does anybody have any insight on this?  I don't remember this
> >> happening until fairly recently, but don't know if it dates to when I
> >> started switch~ing modules.  I'm currently running 0.39.2-extended
> >> RC1 on a MacBook Pro.
> >>
> >>
> >> Phil Stone
> >>
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>
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