Suliman:
Could anybody explain why there is opinion that stack is fast and the heap is slow. All of them are located in the same memory. So the access time should be equal.
Often the access speed is not exactly the same, because the stack memory is usually hotter, this means it's more often kept in one of the CPU caches. But that's not the speed difference they usually talk about. They refer to the time needed to allocate and deallocate heap memory, that is often higher (and unpredictable) compared to allocating some stack memory. If you have a good GC like the OracleVM ones, allocating memory is very fast (sometimes little more than a comparison and an increase, thank to the green generation that is handled as a stack), but still not as fast as allocating and freeing stack memory. The situation is quite more complex than what I have explained. There are even CPUs with programmer-controlled scratch memory, instead of just an automatic managed hierarchy of caches.
Bye, bearophile
