[chuck-users] 147th shred removed...segmentation fault? (Ryan Supak)

[Perry R Cook]

I have lots of programs that spork hundreds or thousands
of shreds without this error.  So, without seeing your 
code, my guesses (and questions) are as follows:

Are you running this on a small memory architecture? Since
you say headless, I'm guessing maybe Raspberry Pi?  It
could be that you're running out of memory, so see next 
question.

Does the shred that you're sporking declare new UGs or
require memory to be allocated (arrays, lots of string
manipulation, etc.)?  In general, this is a bad idea if you
can avoid it.  ChucK does no garbage collection, which
means that you need to be cautious about declaring memory.

So even a shred as simple as:

fun void mySine()  {
    SinOsc s => dac;
    Math.random2f(100,1000) => s.freq;
    second => now;
    s =< dac;
}

will eat up memory, because even though the SinOsc
is unchucked and never computes again, the memory
for that structure is still around.  We want, someday
to make ChucK a proper garbage collecting language,
but it's hard, especially for real-time systems.

If this turns out to be your issue, then one way to 
handle this is to make a global pool of fixed 
resources and have your shred grab from that.
Like classic "round robin voice stealing" in 
synthesizers:

SinOsc s[100]; 
0 => int next2Use;

fun void mySine() {
    next2Use => int thisOne;
    1 +=> next2Use;
    if (next2Use > 99) 0 => next2Use;
    s[thisOne] => dac;
    Math.random2f(100,1000) => s[thisOne].freq;
    second => now;
    s[thisOne] =< dac;
}

// to test:
while (1) {
    Math.random2f(0.01,0.1) :: second => now;
    spork ~ mySine();
}

I just fired up a few dozen of these running in 
parallel, VM showed 2600 total shreds running, 
no problem (and no clicks or dropouts!!). 

Hope this helps, if none of this applies, then you
may have discovered a strange bug.  Source code please,
and we can all scratch our heads on it. 

 Thanx!!  PRC


Today's Topics:

   1. 147th shred removed...segmentation fault? (Ryan Supak)