Which is faster: Stack allocation or Heap allocation

Question

This question may sound fairly elementary, but this is a debate I had with another developer I work with.

I was taking care to stack allocate things where I could, i

Answer 1

I don't think stack allocation and heap allocation are generally interchangable. I also hope that the performance of both of them is sufficient for general use.

I'd strongly recommend for small items, whichever one is more suitable to the scope of the allocation. For large items, the heap is probably necessary.

On 32-bit operating systems that have multiple threads, stack is often rather limited (albeit typically to at least a few mb), because the address space needs to be carved up and sooner or later one thread stack will run into another. On single threaded systems (Linux glibc single threaded anyway) the limitation is much less because the stack can just grow and grow.

On 64-bit operating systems there is enough address space to make thread stacks quite large.