Re: Control.Parallel.Strategies.parMap CPU usage

2009-03-30 Thread Christian Höner zu Siederdissen
Hi, thank you very much Simon & Don, for the answers. The latest head gives great results on parallel programs. All cores are now always at work as I hoped for. So, too, thanks to everybody involved in the multicore improvements -- they should come very handy. :-) Thanks again, Christian * Do

Re: Control.Parallel.Strategies.parMap CPU usage

2009-03-30 Thread Don Stewart
choener: > 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

Re: Control.Parallel.Strategies.parMap CPU usage

2009-03-30 Thread Christian Hoener zu Siederdissen
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 star

Re: Control.Parallel.Strategies.parMap CPU usage

2009-03-13 Thread Christian Hoener zu Siederdissen
Simon Marlow wrote: Christian Hoener zu Siederdissen wrote: when using parMap (or parList and demanding) I see a curious pattern in CPU usage. Running "parMap rnf fib [1..100]" gives the following pattern of used CPUs: 4,3,2,1,4,3,2,1,... How did you find out which CPU is being used? Sorr

Re: Control.Parallel.Strategies.parMap CPU usage

2009-03-13 Thread Simon Marlow
Christian Hoener zu Siederdissen wrote: when using parMap (or parList and demanding) I see a curious pattern in CPU usage. Running "parMap rnf fib [1..100]" gives the following pattern of used CPUs: 4,3,2,1,4,3,2,1,... How did you find out which CPU is being used? The fib function requires r

Control.Parallel.Strategies.parMap CPU usage

2009-03-13 Thread Christian Hoener zu Siederdissen
Greetings, when using parMap (or parList and demanding) I see a curious pattern in CPU usage. Running "parMap rnf fib [1..100]" gives the following pattern of used CPUs: 4,3,2,1,4,3,2,1,... The fib function requires roughly two times the time if we go from fib(n) to fib(n+1), meaning that calcu