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 <m...@netris.org> wrote: > I wrote: > > > Nala Ginrut <nalagin...@gmail.com> writes: > >> --------------------cut------------------- > >> scheme@(guile-user)> ,time (define a (map (lambda (x) (expt x 5)) (iota > >> 10000))) > >> ;; 0.008019s real time, 0.007979s run time. 0.000000s spent in GC. > >> scheme@(guile-user)> ,time (define a (par-map (lambda (x) (expt x 5)) > >> (iota 10000))) > >> ;; 6.596471s real time, 6.579375s run time. 1.513880s spent in GC. > >> --------------------end------------------- > > [...] > >> Well, is there any example? > > > > The timings above suggest that, on your machine, the overhead of > > 'par-map' is in the neighborhood of 660 microseconds per thread (that's > > the total run time divided by 10000 iterations). > > I must say that 'par-map' has shockingly poor performance. > We really ought to try to improve this. > > Mark > >
