delphi - What is a safe Maximum Stack Size or How to measure use of stack?

Question

I have an app with a number of worker threads, one for each core. On a modern 8 core machine, I have 8 of these threads. My app loads a lot of plugins, which also have their own worker threads. Because the app uses huge blocks of memory (photos, eg. 200 MB) I have memory fragmentation problem. The problem is that every thread allocates the {$MAXSTACKSIZE ...} of address space. It's not using the physical memory but the adress space. I reduced the MAXSTACKSIZE from 1MB to 128KB and it seems to work, but I don't now if I'm near to the limit. Is there any possibility to measure how much stack is really used?

Answer 1

Use this to compute the amount of memory committed for the current thread's stack:

function CommittedStackSize: Cardinal;
asm
  mov eax,[fs:$4] // base of the stack, from the Thread Environment Block (TEB)
  mov edx,[fs:$8] // address of lowest committed stack page
                  // this gets lower as you use more stack
  sub eax,edx
end;

Another idea I don't have.