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From: Damien Mattei <damien.mattei@gmail.com>
To: guile-user <guile-user@gnu.org>,
	guile-devel <guile-devel@gnu.org>,
	 Olivier Dion <olivier.dion@polymtl.ca>
Subject: Re: map-par slower than map
Date: Thu, 13 Oct 2022 14:36:18 +0200	[thread overview]
Message-ID: <CADEOadcnDfLsFFeMayisQsWw3AuvKb+P1GBmgHGUmSHNQ08U9g@mail.gmail.com> (raw)
In-Reply-To: <CADEOadc3+PhPj_UQz18MJCAC-4T7Xm73F9Wv9Kyf_4nmWXcapQ@mail.gmail.com>

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
>>
>


  reply	other threads:[~2022-10-13 12:36 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-12 17:19 map-par slower than map Damien Mattei
2022-10-12 18:45 ` Maxime Devos
2022-10-12 20:20   ` Damien Mattei
2022-10-12 20:27     ` Damien Mattei
2022-10-12 21:29       ` Zelphir Kaltstahl
2022-10-14  8:21         ` Damien Mattei
2022-10-14  8:38           ` Zelphir Kaltstahl
2022-10-17 13:17             ` Damien Mattei
2022-10-22 16:01               ` Damien Mattei
2022-10-23  1:06                 ` Damien Mattei
2022-10-23 23:18                   ` Zelphir Kaltstahl
2022-10-24  3:56                     ` Keith Wright
2022-10-24  7:03                       ` Zelphir Kaltstahl
2022-10-24  4:39                     ` Damien Mattei
2022-10-25  9:07         ` Mikael Djurfeldt
2022-10-25  9:11           ` Mikael Djurfeldt
2022-10-25 14:09             ` Damien Mattei
2022-11-10 10:32         ` Damien Mattei
2022-11-10 10:41           ` Damien Mattei
2022-11-10 10:52             ` Zelphir Kaltstahl
2022-11-10 13:36               ` Damien Mattei
2022-11-10 17:07           ` Olivier Dion via General Guile related discussions
2022-11-11 10:26             ` Damien Mattei
2022-11-11 12:25               ` Zelphir Kaltstahl
2022-11-11 13:36                 ` Damien Mattei
2022-11-11 13:37                   ` Damien Mattei
2022-11-13  8:23                     ` Damien Mattei
2022-10-12 21:44     ` Maxime Devos
2022-10-12 21:55 ` Olivier Dion via Developers list for Guile, the GNU extensibility library
2022-10-13  7:40   ` Damien Mattei
2022-10-13  8:20     ` Damien Mattei
2022-10-13  9:10     ` Olivier Dion via Developers list for Guile, the GNU extensibility library
2022-10-13 10:44   ` Damien Mattei
2022-10-13 11:00     ` Olivier Dion via Developers list for Guile, the GNU extensibility library
     [not found]       ` <CADEOadfovi8s3OxRcssWOuOW8jjHoL9Z7pD_5FstSm=ZkBHP8g@mail.gmail.com>
2022-10-13 11:57         ` Fwd: " Damien Mattei
2022-10-13 12:36           ` Damien Mattei [this message]
2022-10-13 12:41             ` Olivier Dion via Developers list for Guile, the GNU extensibility library
2022-10-13 13:43               ` Damien Mattei
2022-10-13 14:06                 ` Olivier Dion via Developers list for Guile, the GNU extensibility library
2022-10-13 14:10                   ` Damien Mattei
2022-10-13 14:21                     ` Damien Mattei

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