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From: ludo@chbouib.org (Ludovic Courtès)
To: guile-devel@gnu.org
Subject: Re: Evolution & optimization of the module system
Date: Mon, 09 Apr 2007 01:06:46 +0200	[thread overview]
Message-ID: <873b3aqxdl.fsf@chbouib.org> (raw)
In-Reply-To: 87649p3j29.fsf@zip.com.au

Hi,

Kevin Ryde <user42@zip.com.au> writes:

> One possibility for duplicates would be lazy checking, only check for
> a clash when actually using a symbol.  That's sort of the prolog
> theory: don't worry now about what might never come up.  I suspect the
> total work would end up greater though.

Attached is a patch that implements lazy duplicate checking.  Thus,
`process-duplicates' is gone and `module-variable' plays its role when a
variable is looked up for the first time.  Subsequent lookups result in
a "cache hit", i.e., the result is taken from the "import obarray" which
is used as a cache.

The code is simpler and obviously less memory-hungry than my previous
attempts.  The lazy approach is not very R6RS-friendly, though (see my
earlier post on this topic).

I measured around 20% speedups in "pure startup time".  The measurements
consist in running a dozen of times a program that just does a few
`use-module's and/or `autoload's and measuring the total user execution
time.  Example scripts are available there:

  http://www.laas.fr/~lcourtes/software/guile/startup.scm
  http://www.laas.fr/~lcourtes/software/guile/startup-autoload.scm

These measurements do not account for the overhead introduced in the
variable lookup process, so measurements with actual programs were
needed.  



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  parent reply	other threads:[~2007-04-08 23:06 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-17 15:15 Evolution & optimization of the module system Ludovic Courtès
2007-02-18 23:32 ` Kevin Ryde
2007-02-19  9:24   ` Ludovic Courtès
2007-02-21 22:21     ` Kevin Ryde
2007-02-22  9:20       ` Ludovic Courtès
2007-02-22 22:23         ` Kevin Ryde
2007-02-23 13:15           ` Ludovic Courtès
2007-02-25 23:37             ` Kevin Ryde
2007-02-26 21:15               ` Ludovic Courtès
2007-02-26 22:46                 ` Kevin Ryde
2007-02-27  8:21                   ` Ludovic Courtès
2007-04-08 23:06               ` Ludovic Courtès [this message]
2007-04-08 23:25                 ` Ludovic Courtès
2007-04-08 23:24               ` Ludovic Courtès
2007-04-30  8:39                 ` Ludovic Courtès
2007-05-05 20:48                   ` Ludovic Courtès
2010-07-20 21:20                     ` Andy Wingo
2010-07-20 22:24                       ` Ludovic Courtès

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