Re: Extremely high overhead of 'par-map'

2013-03-30 Thread Ludovic Courtès
Mark H Weaver skribis: > I must say that 'par-map' has shockingly poor performance. > We really ought to try to improve this. IMO we must improve futures, not necessarily ‘par-map’ itself, because lists are not a good data structure for parallel processing anyway (“get rid of cons” said Steele ;

Re: Extremely high overhead of 'par-map'

2013-03-29 Thread Mark H Weaver
Hi Noah, Noah Lavine writes: > Oh, sorry to email twice so soon, but I have an idea for making > par-map usable in more cases: add a keyword argument called > "block-size". Its value should be a positive integer, and the meaning > is to have each thread do block-size iterations. IMO, we should a

Re: Extremely high overhead of 'par-map'

2013-03-29 Thread Noah Lavine
Oh, sorry to email twice so soon, but I have an idea for making par-map usable in more cases: add a keyword argument called "block-size". Its value should be a positive integer, and the meaning is to have each thread do block-size iterations. That should make it easier to use par-map for cases like

Re: Extremely high overhead of 'par-map'

2013-03-29 Thread Noah Lavine
I agree. Do you have any idea what's causing the overhead? I tried to benchmark it, but got a segmentation fault. I think we have plenty of work to do here. :-) Noah On Fri, Mar 29, 2013 at 2:00 AM, Mark H Weaver wrote: > I wrote: > > > Nala Ginrut writes: > >> cut---