Re: [msysGit] Re: [PATCH] Add custom memory allocator to MinGW and MacOS builds

From: Pat Thoyts <patthoyts@googlemail.com>
Date: Apr 3, 2009, 21:12 UTC
Message-ID: <a5b261830904031412o60b7eb4fv7e25a2ca4f89fe60@mail.gmail.com>
In-Reply-To: <49D61B35.8060508@trolltech.com>

2009/4/3 Marius Storm-Olsen <marius@trolltech.com>:

Show 16 quoted lines

>
> Marius Storm-Olsen said the following on 03.04.2009 15:52:
>> The standard allocator on Windows is pretty bad prior
>> to Windows Vista, and nedmalloc is better than the
>> modified dlmalloc provided with newer versions of the
>> MinGW libc.
>
> Actually, it just struck me that it's probably the synchronization
> primitives which are better on Vista than XP, and not the memory
> manager? (Since mingw 4.3.3-tdm on XP and Vista most likely use the
> same dlmalloc fork?) ^shrug^
>
> Anyways, not that I haven't tried to 'tune' nedmalloc in any way, just
> ensured that it compiles with the different MinGWs which I
> benchmarked. So, if anyone feels like it, maybe we can squeeze more
> performance out of it by tweaking it.

The difference on Windows Vista is that the low fragmentation heap is the default memory allocator. On Windows XP you need to enable it specifically for an application. So a possible alternative to this is just to enable the low fragmentation heap. (done via GetProcessHeaps and HeapSetInformation Win32 API calls).

Pat Thoyts