Re: [Haskell-cafe] SMP parallelism increasing GC time dramatically

I don't know if this is relevant to your problems, but I'm currently struggling to get some performance out of a parallel - or rather, concurrent - program. Basically, the initial thread parses some data into an IntMap, and then multiple threads access this read-only to do the Real Work. Now, there appears to be a lot of overhead incurred when using multiple threads, and I suspect that this is caused by the map storing unevaluated thunks, which then are forced by accesses by the worker threads. Ideally, the evaluation should be performed in parallel, but perhaps there are issues (of synchronization, say) that makes this less performant? -k -- If I haven't seen further, it is by standing in the footprints of giants