ntdll: Heap implementation has a performance bottleneck
Michael Kaufmann
hallo at michael-kaufmann.ch
Tue Jul 18 16:21:09 CDT 2006
Hi,
I have discovered that Wine's heap implementation (HeapAlloc(),
HeapFree(), etc. in dlls/ntdll/heap.c) is very slow if many small memory
blocks are allocated and freed. Somebody has reported this before:
http://www.winehq.org/pipermail/wine-devel/2005-February/034095.html
HomeSite's syntax checker needs 120 seconds to load on Wine because of
Wine's poor heap implementation. Most users will think that the program
has crashed. I have created a trace of HomeSite's memory requests and a
program to replay them. For details and performance measurements, please
look at bug 5709 ( http://bugs.winehq.org/show_bug.cgi?id=5709 ).
According to the source code, Wine's heap implementation is described in
the book "Windows 95 System Programming Secrets". This implementation is
inefficient: KB225099 ( http://support.microsoft.com/kb/225099/en-us )
says that the heap implementation of Windows NT 4.0 SP4 and 2000 is much
better than the heap implementation of Windows 95.
Does anybody know some details about the heap implementation of Windows
NT/2000/XP ?
Regards,
Michael
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