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Re: map-par slower than map
From: |
Damien Mattei |
Subject: |
Re: map-par slower than map |
Date: |
Thu, 13 Oct 2022 14:36:18 +0200 |
the code did not worked when data length were more little than number of
cpus (6 on my host) (iota 5) returns #unsepcified:
scheme@(guile-user)> (use-modules (ice-9 threads))
scheme@(guile-user)> {v <+ (list->vector (iota 5))}
#(0 1 2 3 4)
scheme@(guile-user)> (par-map-vector sqrt v)
scheme@(guile-user)> {v <+ (list->vector (iota 20))}
#(0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19)
scheme@(guile-user)> (par-map-vector sqrt v)
#(0 1 1.4142135623730951 1.7320508075688772 2 2.23606797749979
2.449489742783178 2.6457513110645907 2.8284271247461903 3
3.1622776601683795 3.3166247903554 3.4641016151377544 3.605551275463989
3.7416573867739413 3.872983346207417 4 4.123105625617661 4.242640687119285
4.358898943540674)
scheme@(guile-user)> (current-processor-count)
6
scheme@(guile-user)> {v <+ (list->vector (iota 6))}
#(0 1 2 3 4 5)
scheme@(guile-user)> (par-map-vector sqrt v)
#(0 1 1.4142135623730951 1.7320508075688772 2 2.23606797749979)
so i modify it this way:
(define* (par-map-vector proc input
#:optional
(max-thread (current-processor-count)))
(if (< (vector-length input) max-thread)
(list->vector (map proc (vector->list input))) ;; less data than
threads or CPUs
(let* ((block-size (quotient (vector-length input) max-thread))
(rest (remainder (vector-length input) max-thread))
(output (make-vector (vector-length input) #f)))
(when (not (zero? block-size))
(let ((mtx (make-mutex))
(cnd (make-condition-variable))
(n 0))
(fold
(lambda (scale output)
(begin-thread
(let lp ((i 0))
(when (< i block-size)
(let ((i (+ i (* scale block-size))))
(vector-set! output i (proc (vector-ref input i))))
(lp (1+ i))))
(with-mutex mtx
(set! n (1+ n))
(signal-condition-variable cnd)))
output)
output
(iota max-thread))
(with-mutex mtx
(while (not (< n max-thread))
(wait-condition-variable cnd mtx))))
(let ((base (- (vector-length input) rest)))
(let lp ((i 0))
(when (< i rest)
(let ((i (+ i base)))
(vector-set! output i (proc (vector-ref input i))))
(lp (1+ i)))))
output))))
now it works but crash randomly, not even at the same stage, i continue to
test and debug....
On Thu, Oct 13, 2022 at 1:57 PM Damien Mattei <damien.mattei@gmail.com>
wrote:
> sorry google always do reply to single author...
>
> ---------- Forwarded message ---------
> From: Damien Mattei <damien.mattei@gmail.com>
> Date: Thu, Oct 13, 2022 at 1:56 PM
> Subject: Re: map-par slower than map
> To: Olivier Dion <olivier.dion@polymtl.ca>
>
>
> ah just at the end? i had noticed, but i get #unspecifeid ? so my new code
> is not good if your procedure is, i will check it,thanks.
> Damien
>
> On Thu, Oct 13, 2022 at 1:00 PM Olivier Dion <olivier.dion@polymtl.ca>
> wrote:
>
>> On Thu, 13 Oct 2022, Damien Mattei <damien.mattei@gmail.com> wrote:
>> > i trying to use your code but it seems there is a ) mismatch
>> > somewhere?
>>
>> Right there's a missing ')' a the end to close the procedure, sorry
>> about that.
>>
>> --
>> Olivier Dion
>> oldiob.dev
>>
>
Re: map-par slower than map, Olivier Dion, 2022/10/12
- Re: map-par slower than map, Damien Mattei, 2022/10/13
- Re: map-par slower than map, Damien Mattei, 2022/10/13
- Re: map-par slower than map, Olivier Dion, 2022/10/13
- Message not available
- Fwd: map-par slower than map, Damien Mattei, 2022/10/13
- Re: map-par slower than map,
Damien Mattei <=
- Re: map-par slower than map, Olivier Dion, 2022/10/13
- Re: map-par slower than map, Damien Mattei, 2022/10/13
- Re: map-par slower than map, Olivier Dion, 2022/10/13
- Re: map-par slower than map, Damien Mattei, 2022/10/13
- Re: map-par slower than map, Damien Mattei, 2022/10/13