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[Cs-dev] Multiprocessing in Max/MSP 5.0

Date2008-06-25 22:03
FromMichael Gogins
Subject[Cs-dev] Multiprocessing in Max/MSP 5.0
According to a product announcement in the summer Computer Music Journal which is just out, the new version of Max is designed for multi-threading on multi-core computers. I will investigate further.

Regards,
Mike





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Date2008-06-25 23:54
Fromdp51
SubjectRe: [Cs-dev] Multiprocessing in Max/MSP 5.0
I've done some experimentation with the [poly~] external running in
multithreaded mode (using
the "parallel" and "threadcount" messages) on a Core 2 Duo iMac.  

At first, I thought it wasn't working because I was relying on Apple's
Activity Monitor to see a performance benefit.  Whenever I increased the
threadcount to 2, the "% CPU" column would increase and I could not detect
any changes in the CPU histogram.  But Max was telling me that CPU usage was
nearly cut in half.

I decided to instantiate [poly~] with just enough voices to get audio
breakups.  Then I increased threadcount to 2 and got no breakups.  After 2,
I could see the thread overhead start to build up as one would expect.  I
then tried to see how many voices I could get with different threadcounts. 
I got 6 voices on 1 thread without breakups, and 10 voices on 2 threads
without breakups.  So, I'm convinced that [poly~] multithreading is working.  

Although [poly~] makes copies of a single patch, you can target individual
voices when sending values and messages.  So in theory (haven't tried it
yet) you could run different CSD files (using [csound~]) within one [poly~]. 
Sounds like a fun weekend project :)

Davis
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