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Re: Allocation zones question
From: |
Richard Frith-Macdonald |
Subject: |
Re: Allocation zones question |
Date: |
Fri, 8 Nov 2002 08:49:03 +0000 |
On Friday, November 8, 2002, at 08:06 am, Stefan Urbanek wrote:
Hi,
I was reading comments about OSX speed on /. and someone did mentioned:
"...The use of allocation zones can also speed up the VM system a
great deal ..."
I know, that in comments on /. there you may find anything, but
anyway, I am just interested in whether that statement about zones and
speedup is true or not. If yes, how it is possible and is it true also
for GNUstep?
IMO zones are an added complexity that we could well do without.
While it's true in theory that using a zone to allocate a set of
objects can localize them in memory and improve speed by thus aiding
caching and minimising the work the VM system has to do, in practice
the VM code of modern systems such as linux and bsd is such that any
improvement is very marginal (I couldn't detect it in simple tests a
few years ago).
There may be a few cases where it can still help .... for instance
allocating specialised objects within their own zone and destroying
them at one go by destroying the zone, but I think the effort is
probably not worthwhile.