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Re: [Gcl-devel] Re: [Maxima] Re: Lisp vs. Java vs. C++ speed comparison

From: Vadim V. Zhytnikov
Subject: Re: [Gcl-devel] Re: [Maxima] Re: Lisp vs. Java vs. C++ speed comparison time? [LONG]
Date: Sun, 11 Jul 2004 15:36:30 +0400
User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.6) Gecko/20040407

Camm Maguire writes:

"Vadim V. Zhytnikov" <address@hidden> writes:

Valery Pipin writes:

On Saturday 03 July 2004 01:42, Camm Maguire wrote:

All lisps here are the latest versions in Debian unstable.  GCL was
run in ANSI mode.  The machine was a dual Xeon 2.4Ghz.  We already
know that the relative GCL/CMUCL performance can vary somewhat by
machine, presumably influenced by cache size and cpu/memory bandwidth
ratios.  It is clear for example that CMUCL is doing a better job on
the memory layout/access times which predominate in the gc time

Is that the reason why  I do not observe the memory leakage with maxima 
computations  that done with cmucl
implementation. In opposite, the gcl implementation can consume so much memory 
that I force to restart the x-session
or even to reboot PC.

I don't think this is memory leak.  Gcl memory layout is less
compact compared to one of cmucl. The same computation on GCL
require more RAM and it starts swapping earlier.

This is an interesting observation.  If you can quantify this with
some reproducible examples, we might be able to take a look at it.

It's actually very simple observation.  Start lisp,
and make 10000000 long list.  Something like
(progn (setq w (make-list 10000000)) nil)
For clisp and cmucl this operation extends
RAM by ~80Mb while for GCL it requires ~120Mb.
It is clear that GCL uses 3 words for one cons
cell while cmucl and clisp use 2 words.
I wonder what is gcl cons cell size on 64bit

     Vadim V. Zhytnikov


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