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Re: Cheap malloc()

From glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups comp.lang.c
Subject Re: Cheap malloc()
Date 2015-10-08 01:10 +0000
Organization Aioe.org NNTP Server
Message-ID <mv4fpi$5to$1@speranza.aioe.org> (permalink)
References <mutp9b$1s8$1@solani.org> <muu8r7$4mi$1@speranza.aioe.org> <mv34es$a0v$2@solani.org>

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Philipp Klaus Krause <pkk@spth.de> wrote:

(snip, regarding malloc() strategy, I wrote)

>> Searching a linked list is O(N). If you do it N times, the result
>> is O(N**2). It is not cache friendly or virtual memory friendly.
 
> But as long as there is no fragmentation, malloc will work in O(1),since
> the first element in the list will always be the only free block, which
> will contain all free memory, making it fast.

The case that interests me most is web browsers. After some time,
accessing pages, switching tabs, accessing more, and especially
if any are facebook, browsers start paging. You switch tabs, and
wait seconds or even minutes for paging until it updates the screen.

You are very lucky if you avoid fragmentation. That is rare.

-- glen

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Thread

Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-05 14:09 +0200
  Re: Cheap malloc() Robert Wessel <robertwessel2@yahoo.com> - 2015-10-05 09:52 -0500
  Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-05 11:04 -0400
    Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-05 20:36 -0500
    Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-06 07:54 -0400
      Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-06 08:06 -0500
        Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-07 07:46 -0400
          Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-07 07:35 -0500
      Re: Cheap malloc() glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-06 23:29 +0000
  Re: Cheap malloc() supercat@casperkitty.com - 2015-10-05 08:12 -0700
  Re: Cheap malloc() glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-05 16:34 +0000
    Re: Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-07 14:50 +0200
      Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-07 08:45 -0500
        Re: Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-07 19:33 +0200
          Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-07 15:40 -0500
      Re: Cheap malloc() glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-08 01:10 +0000
        Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-08 08:08 -0400
  Re: Cheap malloc() Bartc <bc@freeuk.com> - 2015-10-06 13:47 +0100
    Re: Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-07 14:48 +0200

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