Tools to view/solve Windows XP memory fragmentation

Question

We have a java program that requires a large amount of heap space - we start it with (among other command line arguments) the argument -Xmx1500m, which specifies a maximum h

Answer 1

Agree with Torlack, a lot of this is because other DLLs are getting loaded and go into certain spots, breaking up the amount of memory you can get for the VM in one big chunk.

You can do some work on WinXP if you have more than 3G of memory to get some of the windows stuff moved around, look up PAE here: http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx

Your best bet, if you really need more than 1.2G of memory for your java app, is to look at 64 bit windows or linux or OSX. If you're using any kind of native libraries with your app you'll have to recompile them for 64 bit, but its going to be a lot easier than trying to rebase dlls and stuff to maximize the memory you can get on 32 bit windows.

Another option would be to split your program up into multiple VMs and have them communicate with eachother via RMI or messaging or something. That way each VM can have some subset of the memory you need. Without knowing what your app does, i'm not sure that this will help in any way, though...