bug#14756: threads - par-map - multicore issue

[Andy Wingo]

I see this, but I'm not quite sure what's going on.  What I do see is
that par-map of 1+ on a list is horribly slow, both on 2.0 and master.
Ludovic do you know what's going on here?

Andy

On Sun 30 Jun 2013 20:00, David Pirotte <address@hidden> writes:

> Hello,
>
>       guile --version
>       guile (GNU Guile) 2.0.9.20-10454
>
> It seems that the par-map not using all cores problem has some how been 
> reintroduced?
>
>       guile -c '(begin (use-modules (ice-9 threads)) (par-map 1+ (iota 
> 400000)))'
>
> only uses 1 core [it seems it uses some other [maybe all, i can't tell] a 
> couple of
> milliseconds, then drops to 1 core only.
>
> Thanks,
> David
>
> ;; -- 
>
> address@hidden:~ 16 $ guile -c '(begin
>>     (use-modules (ice-9 threads))
>>     (par-map 1+ (iota 400))
>>     (display (current-processor-count)) (display "\n")
>>     (display (length (@@ (ice-9 futures) %workers))) (display "\n"))'
> 12
> 11