Mac Forum / Programming / CodeWarrior / January 2005

I'm trying to optimize the memory use of my Mach-O application
(CodeWarrior C++ application, using PowerPlant and now PPx).  My
application is very dynamic: lots of allocations and deallocations using
new/free in C++ and a few mallocs and NewPtrs thrown in here and there
as required.

When I am watching it run using MallocDebug, it looks like I am
appropriately deallocating objects that I don't need (i.e. no leaks).  
However, the longer I run, doing various memory-intensive tasks that
allocate and deallocate, the more private/resident memory I seem to be
using according to top.  One clue is MREGS which is quite large (290 at
this point; however, CodeWarrior is using 1355).  MallocDebug will say
that I'm using about 4MB of allocated space, while top will say that I'm
using 40-50M of private address space and hundreds of MB of total VM.  
Seems strange.

So, I am assuming that, although I am not using much real memory, it is
fragmented and the memory manager can't consolidate regions.

Is it a problem if the resident private address space size is large,
even if the application is not using the memory?  Is there a way to
force consolidation if possible?  I don't know the CW memory management
code that well, especially with respect to interaction with the Mach VM.  
Are there other memory allocator options that might be more well-behaved?

Hints and suggestions appreciated.

Thanks--

  Bruce