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