From: David Kastrup <dak@gnu.org>
To: Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>
Cc: torvalds@linux-foundation.org, nico@cam.org,
jonsmirl@gmail.com, gitster@pobox.com, gcc@gcc.gnu.org,
git@vger.kernel.org
Subject: Re: Something is broken in repack
Date: Fri, 14 Dec 2007 16:59:00 -0000 [thread overview]
Message-ID: <85r6hptecs.fsf@lola.goethe.zz> (raw)
In-Reply-To: <20071214161236.3080.qmail@md.dent.med.uni-muenchen.de> (Wolfram Gloger's message of "14 Dec 2007 16:12:36 -0000")
Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> writes:
> Hi,
>
>> Note that delta following involves patterns something like
>>
>> allocate (small) space for delta
>> for i in (1..depth) {
>> allocate large space for base
>> allocate large space for result
>> .. apply delta ..
>> free large space for base
>> free small space for delta
>> }
>>
>> so if you have some stupid heap algorithm that doesn't try to merge and
>> re-use free'd spaces very aggressively (because that takes CPU time!),
>
> ptmalloc2 (in glibc) _per arena_ is basically best-fit. This is the
> best known general strategy,
Uh what? Someone crank out his copy of "The Art of Computer
Programming", I think volume 1. Best fit is known (analyzed and proven
and documented decades ago) to be one of the worst strategies for memory
allocation. Exactly because it leads to huge fragmentation problems.
--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
next prev parent reply other threads:[~2007-12-14 16:44 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <9e4733910712071505y6834f040k37261d65a2d445c4@mail.gmail.com>
[not found] ` <9e4733910712101825l33cdc2c0mca2ddbfd5afdb298@mail.gmail.com>
[not found] ` <alpine.LFD.0.99999.0712102231570.555@xanadu.home>
[not found] ` <9e4733910712102125w56c70c0cxb8b00a060b62077@mail.gmail.com>
2007-12-11 7:01 ` Jon Smirl
2007-12-11 7:34 ` Jon Smirl
2007-12-11 11:11 ` Andreas Ericsson
2007-12-11 15:01 ` Nicolas Pitre
2007-12-11 15:36 ` Nicolas Pitre
2007-12-11 16:20 ` Jon Smirl
2007-12-11 16:22 ` Nicolas Pitre
2007-12-11 16:34 ` Jon Smirl
2007-12-12 7:25 ` Nicolas Pitre
2007-12-12 12:02 ` David Kastrup
2007-12-14 16:44 ` Wolfram Gloger
2007-12-12 16:14 ` Nicolas Pitre
2007-12-12 16:37 ` Paolo Bonzini
2007-12-12 16:42 ` Linus Torvalds
2007-12-12 16:54 ` David Miller
2007-12-12 17:12 ` Linus Torvalds
2007-12-12 17:29 ` Jon Smirl
2007-12-14 16:19 ` Wolfram Gloger
2007-12-14 16:59 ` David Kastrup [this message]
2007-12-14 18:49 ` Wolfram Gloger
2007-12-13 14:09 ` Nguyen Thai Ngoc Duy
[not found] ` <fjrj9k$n6k$1@ger.gmane.org>
2007-12-13 16:39 ` Paolo Bonzini
2007-12-13 17:40 ` Johannes Sixt
2007-12-14 2:31 ` Jakub Narebski
[not found] ` <fjt6vm$n7d$1@ger.gmane.org>
2007-12-14 6:39 ` Nguyen Thai Ngoc Duy
2007-12-14 9:02 ` Paolo Bonzini
2007-12-14 9:39 ` Harvey Harrison
2007-12-14 10:52 ` Jakub Narebski
2007-12-14 13:25 ` Nguyen Thai Ngoc Duy
2007-12-14 13:53 ` Nicolas Pitre
2007-12-12 16:19 ` Nicolas Pitre
2007-12-13 7:39 ` Andreas Ericsson
2007-12-14 16:12 ` Wolfram Gloger
2007-12-11 17:19 ` Linus Torvalds
2007-12-11 17:24 ` Nicolas Pitre
2007-12-11 17:28 ` David Miller
2007-12-11 18:43 ` Nicolas Pitre
2007-12-11 20:34 ` Andreas Ericsson
2007-12-11 18:57 ` Jon Smirl
2007-12-11 19:17 ` Nicolas Pitre
2007-12-11 19:40 ` Linus Torvalds
2007-12-11 20:26 ` Junio C Hamano
2007-12-12 5:06 ` Andreas Ericsson
2007-12-11 17:44 ` Daniel Berlin
2007-12-11 13:49 ` Nicolas Pitre
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