Re: Memory management and custom allocator

From	Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups	comp.lang.c
Subject	Re: Memory management and custom allocator
Date	2011-12-31 14:30 -0500
Organization	A noiseless patient Spider
Message-ID	<jdnnsh$j0v$1@dont-email.me> (permalink)
References	<911c685c-3bf9-4079-bf61-66342d8a8c2c@u6g2000vbc.googlegroups.com> <20111231091520.131@kylheku.com> <67cb95d9-a8ef-4e34-9def-a5163e008862@n6g2000vbg.googlegroups.com>

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On 12/31/2011 12:52 PM, FtM wrote:
> On Dec 31, 6:24 pm, Kaz Kylheku<k...@kylheku.com>  wrote:
>> On 2011-12-31, FtM<fmas...@gmail.com>  wrote:
>>
>>> I would like to implement my custom allocator for the *nix and windows
>>> systems too (of course loosing some portability for performance gain),
>>> and maybe implement something like the C++ allocators to improve the
>>> memory management of the different algorithms (like rare large
>>> allocations on vectors / frequent small allocations on lists), but
>>
>> What makes you think that your malloc doesn't already handle
>> such cases?
>>
>
> Simply because it can't know if I'm going to do 200 little allocations
> or 1 big one. Even if it has the most neat heuristic ever, the libc
> (or the kernel) exposing a simple specific function/syscall would do
> its job way better. Part of the question was about this hypothetical
> function.

     Why do you think the kernel predicts your program's future behavior
better than malloc() does?

> I already said that I don't want to "beat malloc", just to find a
> (probably platform-specific) way to facilitate its job.

     Both the kernel and malloc() have a hard time predicting your
program's behavior, but I'll risk a prediction for the New Year:

	You will not invent a "general low-level" replacement that
	outperforms malloc() et al.

> [...] I'm just
> asking how to deal with the two specific environments above while
> masking the differences between the two and maintaining a standard
> interface.

     Easy: Use malloc() et al., right out of the box.  Platform
specifics are already masked, system-specific dodges and tricks are
already employed, code is already tested and debugged to a degree
that you cannot possibly replicate.

     There!  Wasn't that easy?

-- 
Eric Sosman
esosman@ieee-dot-org.invalid

Thread

[Slightly OT] Memory management and custom allocator FtM <fmassei@gmail.com> - 2011-12-31 06:56 -0800
  Re: [Slightly OT] Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-31 11:08 -0500
    Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2011-12-31 08:28 -0800
  Re: [Slightly OT] Memory management and custom allocator Johann Klammer <klammerr@NOSPAM.aon.at> - 2011-12-31 17:39 +0100
    Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2011-12-31 08:55 -0800
      Re: Memory management and custom allocator Johann Klammer <klammerr@NOSPAM.aon.at> - 2011-12-31 19:01 +0100
        Re: Memory management and custom allocator Kaz Kylheku <kaz@kylheku.com> - 2011-12-31 18:31 +0000
  Re: [Slightly OT] Memory management and custom allocator Kaz Kylheku <kaz@kylheku.com> - 2011-12-31 17:24 +0000
    Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2011-12-31 09:52 -0800
      Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-31 14:30 -0500
      Re: Memory management and custom allocator Markus Wichmann <nullplan@gmx.net> - 2012-01-01 12:21 +0100
        Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-01 12:54 +0000
          Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-01 09:03 -0500
            Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-01 16:23 +0000
            Re: Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-01 21:41 +0000
              Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-02 08:10 -0500
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-02 14:07 +0000
                Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-02 09:47 -0500
                Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-02 08:36 -0800
                Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-02 13:43 -0500
                Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-02 11:38 -0800
                Re: Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-03 13:14 +0000
                Re: Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-03 06:07 -0800
                Re: Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-05 17:06 -0800
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-02 21:36 +0000
                Re: Memory management and custom allocator Kaz Kylheku <kaz@kylheku.com> - 2012-01-02 21:44 +0000
                Re: Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-02 23:10 -0800
                Re: Memory management and custom allocator Keith Thompson <kst-u@mib.org> - 2012-01-02 13:42 -0800
                Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-02 17:38 -0500
                Re: Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-02 21:45 +0000
                Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-02 18:19 -0500
                Re: Memory management and custom allocator Keith Thompson <kst-u@mib.org> - 2012-01-02 15:42 -0800
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-02 23:59 +0000
                Re: Memory management and custom allocator Kleuske <kleuske@nowhere.net> - 2012-01-03 11:38 +0000
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-03 12:49 +0000
                Re: Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-04 23:42 +0000
                Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-04 20:23 -0500
                Re: Memory management and custom allocator Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-01-05 23:31 +0200
                Re: Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-04 21:52 +0000
                Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-04 20:31 -0500
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-05 01:45 +0000
                Re: Memory management and custom allocator Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-01-07 05:55 +0200
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-07 12:02 +0000
          Re: Memory management and custom allocator Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-01 09:08 -0500
            Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-01 10:08 -0800
              Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-01 23:34 +0000
                Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-02 02:18 -0800
                Re: Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-02 02:34 -0800
                Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-02 02:43 -0800
                Re: Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-02 03:11 -0800
                Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-02 08:17 -0800
                Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-02 11:40 +0000
                Re: Memory management and custom allocator FtM <fmassei@gmail.com> - 2012-01-02 08:27 -0800
          Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-01 23:26 +0000
            Re: Memory management and custom allocator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-01 23:54 +0000
              Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-02 00:32 +0000
          Re: Memory management and custom allocator Kaz Kylheku <kaz@kylheku.com> - 2012-01-02 02:46 +0000
            Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-02 11:53 +0000
              Re: Memory management and custom allocator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-02 15:18 +0000
          Re: Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-03 12:21 +0000
          Re: Memory management and custom allocator Karl Malbrain <malbrain@yahoo.com> - 2012-01-04 16:48 -0800
            Re: Memory management and custom allocator "BartC" <bc@freeuk.com> - 2012-01-05 01:36 +0000
  Re: [Slightly OT] Memory management and custom allocator "io_x" <a@b.c.invalid> - 2012-01-01 17:02 +0100
  Re: [Slightly OT] Memory management and custom allocator jgk@panix.com (Joe keane) - 2012-01-01 21:21 +0000
  Re: [Slightly OT] Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-01 21:01 -0800
  Re: [Slightly OT] Memory management and custom allocator 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-07 05:20 -0800

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