Nala Ginrut <[email protected]> writes:
> But I'm still puzzled with the performance of par-map:
> --------------------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-------------------
>
> So my question is, what's the proper scenario to use par-map?
It only makes sense to use 'par-map' when the procedure is fairly
expensive to compute. There is inevitably a lot of overhead in creating
and joining the threads. Granted, we should be able to do much better
than we're doing now, but it would *never* make sense to use 'par-map'
when each computation is as simple as (expt x 5).
Regards,
Mark
