[chuck-users] GC vs real-time (was Getting Started with ChucK)

Kassen signal.automatique at gmail.com
Fri Jul 24 11:59:46 EDT 2009


Hans;
>
>
>
> That is a big problem: Chuck needs to be multi-threaded if it should be
> able to make use of this new computing power.
>

Yes. However using multiple CPU's to distribute the work of a program like
ChucK is a non-trivial matter. For one thing it's not always possible.
consider this;

5 => int n;

SinOsc sines[n];

for(int i; i< sines.cap(); i++)
    {
    2 => sines[i].sync;
    1 + (10*i) => sines[i].gain;
    for(int j; j< sines.cap(); j++)
        {
        if(i != j) sines[i] => sines[j];
        }
    }

sines [0] => dac;
5::second => now;

That is a highly interconnected UGen graph and I think we will agree that
for any CPU there is a number "n" at which point this will no longer run on
that CPU. At that point distributing the calculation will likely not help
you much either, if it's possible at all.

Most UGen graphs aren't like this, however they may become like that due to
new connections made. This means that we may have to re-optimise the whole
graph, relative to the CPU cores, for any connections made. You can then try
to optimise for either a minimum of dropouts or a most efficient use of the
available power.... This is non-trivial. Our friends over in the SC scene
didn't solve that one yet either.


>
> You pick up a PowerBook at a good price in this point of time, but beware
> that the lids of the Ti-books will drop off after some time of use because
> the hinge-structure is weak. But they can still be used, with an external
> display.
>

I personally don't feel Powerbooks suit my particular needs very well. Right
now I think I could get more of a performance boost by getting into
configuring a custom realtime Linux kernel on hardware I already own.


> I haven't seen a floppy drive for a long time, though they seem to have
> been longer in use on the PC side.
>

I don't think that's a Mac/Pc issue, at least it isn't for me. My interest
in them has to do with liking the sound of old samplers and MIDI sample dump
being attrociously slow. Floppies are small, prone to breaking and downright
archaic... but very convenient for feeding samples to old samplers. In my
dream world we could buy a soundcard with hardware plugins for various DA
converters in order to get that type of sound.

Multi-core can still be useful if one can run more than one copy of the
> program.
>

Absolutely.

Kas.
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