Re: [Chicken-users] Memory allocation and limits in chicken scheme programs

[Matt Welland]

On Wed, Dec 13, 2017 at 12:41 PM, Peter Bex <address@hidden> wrote:

On Wed, Dec 13, 2017 at 11:13:54AM -0700, Matt Welland wrote:
> I'm using Chicken 4.10.0 and with the below script chicken rapidly
> allocates memory then seems to get stuck:

Hi Matt,

Try to update to CHICKEN 4.13.0 first (standard advice, we usually
fix lots of issues in new versions).  I simply get this after a few
seconds:

[panic] out of memory - heap has reached its maximum size - execution terminated

The fix is to increase the maximum allowed heap size using -:hm:
csi -:hm4G ./test.scm cleanly exits after a few seconds here with either
version of CHICKEN.

> The program chokes after 133 rounds through the loop. No "out of memory'
> message.

I suppose that's a bug we fixed in 4.13.0; I seem to recall an issue like
that where allocating near the maximum heap size would result in it
triggering a GC, then filling up the heap immediately again etc, resulting
in a GC loop, but I can't find it in NEWS right now.

Much better with 4.13. Thanks. I have it working up to 128G. I don't understand the heap and will do some more reading but am I correct in assuming that the size of the heap will determine the largest data structure I can have in memory? I base this on seeing the VIRT column in htop plateau at 128G when I used -:nm128G. 

 

> The process memory usage doesn't seem to grow and the program just
> hangs. I added -B: but didn't get any output.

Try the -:g option (debugging output for the GC); you'll quickly see that
it's resizing the heap all the time to the same limit.

Cheers,
Peter