[PD] switch~ & cputime climbing

[Phil Stone]

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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