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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: bug#13188: 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__23214.3164765604$1364439438$gmane$org@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: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-15  8:12 bug#13188: par-map causes VM stack overflow Nala Ginrut
2013-03-27 17:12 ` Ludovic Courtès
2013-03-28  2:55   ` Nala Ginrut [this message]
     [not found]   ` <1364439334.2730.41.camel@Renee-desktop.suse>
2013-03-28  5:05     ` bug#13188: Whats' the proper senario of par-map? (Was Re: bug#13188: par-map causes VM stack overflow) Mark H Weaver
     [not found]     ` <874nfwazc3.fsf@tines.lan>
2013-03-28 13:44       ` Ludovic Courtès
     [not found]       ` <87r4izprks.fsf@gnu.org>
2013-03-28 18:00         ` Mark H Weaver
     [not found]         ` <87ip4b9zfv.fsf@tines.lan>
2013-03-28 20:07           ` Ludovic Courtès
2013-03-29  2:36       ` Nala Ginrut
     [not found]       ` <1364524610.2730.48.camel@Renee-desktop.suse>
2013-03-29  9:52         ` Ludovic Courtès

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