[Haskell-cafe] Threading and Mullticore Computation

Andrew Coppin andrewcoppin at btinternet.com
Tue Mar 3 13:28:30 EST 2009

Svein Ove Aas wrote:
> For what it's worth, I tried it myself on 6.10.. details follow, but
> overall impression is that while you lose some time to overhead, it's
> still 50% faster than unthreaded.

Damn. Somebody beat me to it. :-)

> While trying to optimize it, I ran "./test +RTS -N2 -H64m -M64m"; the
> program promptly ate all my memory, invoking the OOM killer and
> messing up my system something fierce. This has to be a bug.

I should point out that approximately 50% of the time, the -N2 version 
exits with "Cores1: out of memory" rather than running to completion. 
The -N1 version never does this.

I hadn't looked at RAM usage, but it does appear that both programs 
use... rather a lot of this. (Measurable in gigabytes.) Space leak, 
anyone? (Presumably in fac or fac'.)

More information about the Haskell-Cafe mailing list