On Mon, Dec 13, 2010 at 10:17 AM, Mathieu Boespflug
Hi John,
Why don't you use ulimit for this job?
By default, the GHC runtime will allocate memory beyond what it takes for takes to cause thrashing on a Linux box. However, if you give the GHC runtime a limit with the -M option, and it wants too much memory, the GHC runtime is smart enough not to ask for more, but to garbage collect more often. If you ulimit the GHC runtime, the process is killed when it asks for too much memory, right? I have enclosed a small script I contributed in another thread that shows how I tested it. If you run my cpsagraph program on my laptop with a large, but not too large input, the program causes OS thrashing and takes ten minutes to run. If you limit the memory using, the script chooses a limit around 750m, and the program completes in 48 seconds! The top program shows that the program gets 100% of the CPU during the fast run. The script chooses the best memory limit, not too small, and not too big. John