From: Andy Wingo <wingo@pobox.com>
To: Luca Saiu <positron@gnu.org>
Cc: bug-guile@gnu.org
Subject: Re: High run time variance
Date: Thu, 05 Aug 2010 16:45:41 +0200 [thread overview]
Message-ID: <m34of92k4q.fsf@unquote.localdomain> (raw)
In-Reply-To: <4C5ABFAB.2080006@gnu.org> (Luca Saiu's message of "Thu, 05 Aug 2010 15:42:03 +0200")
Hi,
On Thu 05 Aug 2010 15:42, Luca Saiu <positron@gnu.org> writes:
> ;;; Why does this GCs after creating b? Try running this with GC_PRINT_STATS=1,
> ;;; or with GC_DONT_GC=1 if you want to see the memory use rise.
>
> (define size 100000)
> (define times 100)
>
> (define b (make-bitvector size))
>
> (do ((t 0 (1+ t)))
> ((= t times) 'done)
> (do ((i 0 (1+ i)))
> ((= i size) 'done)
> (bitvector-set! b i #t)))
The toplevel references to bitvector-set! don't get cached, so the
bitvector-set! gets looked up every time, and there is some unfortunate
allocation in scm_from_locale_symboln. If you put it in a function,
the variable gets cached, and there's no allocation.
Andy
--
http://wingolog.org/
next prev parent reply other threads:[~2010-08-05 14:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-29 16:09 High run time variance Luca Saiu
2010-03-30 9:16 ` Ludovic Courtès
2010-03-30 12:35 ` Luca Saiu
2010-03-30 13:01 ` Ludovic Courtès
2010-03-30 15:05 ` Luca Saiu
2010-08-04 19:51 ` Andy Wingo
2010-08-05 13:42 ` Luca Saiu
2010-08-05 14:45 ` Andy Wingo [this message]
2010-08-05 16:21 ` Luca Saiu
2010-08-05 17:43 ` Andy Wingo
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