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 <mhw@netris.org> wrote:

> I wrote:
>
> > Nala Ginrut <nalaginrut@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
>
>