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From: Nala Ginrut <nalaginrut@gmail.com>
To: "Ludovic Courtès" <ludo@gnu.org>, guile-devel@gnu.org
Cc: 13188-done@debbugs.gnu.org
Subject: Whats' the proper senario of par-map? (Was Re: bug#13188: par-map causes VM stack overflow)
Date: Thu, 28 Mar 2013 10:55:34 +0800	[thread overview]
Message-ID: <1364439334.2730.41.camel@Renee-desktop.suse> (raw)
In-Reply-To: <87y5d8rclr.fsf@gnu.org>

On Wed, 2013-03-27 at 18:12 +0100, Ludovic Courtès wrote:
> Hi,
> 
> Nala Ginrut <nalaginrut@gmail.com> skribis:
> 
> > scheme@(guile-user)> (par-map 1+ (iota 10000))
> > While executing meta-command:
> > ERROR: Throw to key `vm-error' with args `(vm-run "VM: Stack
> > overflow" ())'.
> 
> Commit 8a177d3 fixes this.  I added a paragraph in the documentation
> that explains what happens: delimited continuations to the rescue once
> again!  ;-)
> 
> Comments welcome.
> 

oh~I love delimited continuations!

But I'm still puzzled with the performance of par-map:
--------------------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-------------------

So my question is, what's the proper scenario to use par-map?



> Ludo’.





       reply	other threads:[~2013-03-28  2:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1355559152.27310.5.camel@Renee-desktop.suse>
     [not found] ` <87y5d8rclr.fsf@gnu.org>
2013-03-28  2:55   ` Nala Ginrut [this message]
2013-03-28  5:05     ` Whats' the proper senario of par-map? (Was Re: bug#13188: par-map causes VM stack overflow) Mark H Weaver
2013-03-28 13:44       ` Ludovic Courtès
2013-03-28 18:00         ` Mark H Weaver
2013-03-28 20:07           ` Ludovic Courtès
2013-03-29  2:36       ` Nala Ginrut
2013-03-29  5:49         ` Mark H Weaver
2013-03-29  6:00           ` Extremely high overhead of 'par-map' Mark H Weaver
2013-03-29 20:24             ` Noah Lavine
2013-03-29 20:27               ` Noah Lavine
2013-03-29 23:18                 ` Mark H Weaver
2013-03-30 23:37             ` Ludovic Courtès
2013-03-29 16:45           ` Whats' the proper senario of par-map? (Was Re: bug#13188: par-map causes VM stack overflow) Mark H Weaver
2013-04-01 19:10           ` Andy Wingo
2013-03-29  9:52         ` Ludovic Courtès

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