On Nov 28, 2007 2:39 PM, Matthew Brecknell
Brad Clow:
Don's library is fairly simple. It adds a strictness annotation to force each value you write to a MVar or Chan, so for example, (Control.Concurrent.MVar.Strict.putMVar v x) is basically equivalent to (Control.Concurrent.MVar.putMVar v $! x).
This is useful for returning results from worker threads, because it makes it more likely that the worker thread actually does the work. I say, "more likely", because the strictness annotation only forces the value to WHNF. If you have a deep structure, you might need a more sophisticated forcing function.
When I (deeply) force the worker thread's results to be strict, I observe both cores working, but the execution time (elapsed) slower. As much as a like the Haskell type system, sometimes butting your head up against a wall is less painful than trying to optimise for speed. Regards brad -- www.scoodi.com Recycle is good: Reuse is better