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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 15:43:46 +0200 |
i do not see what has changed in your code ?
really strange,even with bad code the moment it crash should be the same,
sometimes works,crash or freeze....
On Thu, Oct 13, 2022 at 2:41 PM Olivier Dion <olivier.dion@polymtl.ca>
wrote:
> On Thu, 13 Oct 2022, Damien Mattei <damien.mattei@gmail.com> wrote:
> > the code did not worked when data length were more little than number of
> > cpus (6 on my host) (iota 5) returns #unsepcified:
>
> Yeah sorry I miss indended the output and the rest. Here's a version
> that should work:
> --8<---------------cut here---------------start------------->8---
> (use-modules
> (srfi srfi-1)
> (ice-9 threads))
>
> (define* (par-map-vector proc input
> #:optional
> (max-thread (current-processor-count)))
>
> (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))
> --8<---------------cut here---------------end--------------->8---
>
> --
> Olivier Dion
> oldiob.dev
>
- Re: map-par slower than map, (continued)
- 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, 2022/10/13
- Re: map-par slower than map, Olivier Dion, 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, Damien Mattei, 2022/10/13