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'.)