Control.Parallel.Strategies.parMap CPU usage

Don Stewart dons at
Mon Mar 30 13:01:01 EDT 2009

> Hi,
> having tried the 6.10.2rc1 release candidate, I still find that "parMap 
> rnf xs" on a list of thunks xs does not optimally use all available 
> processors. With N the number of cores, I still see that each block of N 
> thunks (say: x_1 and x_2) has to be calculated before (x3 and x4) will be 
> started.
> Would there be hope that compiling the latest head instead of 2009/03/14 (rc1) gives better results?

Yes, definitely. The HEAD implements all the `par` improvements
described in the recent "multicore runtime" paper, as well as giving 
detailed runtime statistics on spark use.

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