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

[Marius Storm-Olsen <mstormo@gmail.com>]

Pat Thoyts said the following on 03.04.2009 23:12:
> 2009/4/3 Marius Storm-Olsen <marius@trolltech.com>:
>> 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).

I know about the low-fragmentation heap, but given that it was only 
supported on XP and up (and given that I also had MacOSX in mind when 
considering a custom allocator; see MacOSX got 12% itself ;-), I 
didn't even consider it.
Thanks for clearing up the differences on the Vista and XP benchmarks 
though! Makes sense.

--
.marius