*BSD News Article 50757


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From: nate@trout.sri.MT.net (Nate Williams)
Newsgroups: comp.unix.bsd.freebsd.misc,comp.os.linux
Subject: Re: FreeBSD page better than Linux?
Date: 7 Sep 1995 00:42:54 GMT
Organization: SRI Intl. - Montana Operations
Lines: 46
Message-ID: <42lf6e$f17@helena.MT.net>
References: <42cnbp$mit@blackice.winternet.com> <42iejc$hkl@agate.berkeley.edu> <42iicc$hlk@news.jf.intel.com> <MICHAELV.95Sep5185933@MindBender.HeadCandy.com>
Reply-To: "Nate Williams" <nate@sneezy.sri.com>
NNTP-Posting-Host: trout.sri.mt.net
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:5787 comp.os.linux:58930

In article <MICHAELV.95Sep5185933@MindBender.HeadCandy.com>,
Michael L. VanLoon <michaelv@MindBender.HeadCandy.com> wrote:
[ FreeBSD using more real memory than Linux in same applications ]

>In article <42iicc$hlk@news.jf.intel.com> haertel@ichips.intel.com (Mike Haertel) writes:

>   If this is true, does anyone have any idea to what extent it might be
>   because FreeBSD is still using the ancient powers-of-two Caltech malloc?
>
>Sounds like a lot of hear-say bull to me...

While I appreciate your comments normally, this 'hear-say bull' is out
of line.  If you haven't done your homework, then don't assume someone
else hasn't either.

[ FYI - Mike is the author of GNU malloc ]

BSD malloc is a *PIG*, and people who have run the exact same programs
on FreeBSD and Linux have seen more real memory used.  This is extermely
obvious in applications such as the X-server, or many memory intensive X
applications.  If linked with GNU-malloc instead of the standard BSD
malloc, real/VM usage of the server is almost always half of what it is
w/out GNU malloc.

However, don't be too alarmed.  First of all, the superior VM system in
FreeBSD makes this problem less noticable, but there's always room for
improvement.

In the last few months work has been done to fix all of the utilities in
the tree which depend on BSD malloc (which returns bzero'd memory). 
Also, a number of people have been looking into different malloc
implementations to replace the stock BSD malloc.  I'm in no position to
make promises, but I expect FreeBSD 2.2 to have a different malloc()
than the stock BSD malloc.

Note, BSD malloc is *extremely* fast, but for most PC systems memory is
the main bottleneck, and not CPU speed.  In the past malloc speed was
critical, but IMHO this is no longer the case.


Nate
-- 
nate@sneezy.sri.com    | Research Engineer, SRI Intl. - Montana Operations
nate@trout.sri.MT.net  | Loving life in God's country, the great state of
work #: (406) 449-7662 | Montana.  Wanna go fly fishing?  I don't charge or
home #: (406) 443-7063 | feed you, but I do know the area pretty well.