Why are stack overflows still a problem?

Question

This question is mystifying me for years and considering this site\'s name, this is the place to ask.

Why do we, programmers, still have this StackOverflow

Answer 1

I think we will see this restriction removed in a few years.

There is simply no fundamental technical reason for fixed size stackes. They exist for historical reasons and because the programmers of compilers and VM's are lazy and don't optimize if it is good enough right now.

But GO the google language already starts with a different approach. It allocates the stack in small 4K pieces. There are also many "stackless" programming language extensions like stackless python etc who are doing the same.

The reason for this is quite simple, the more threads you have the more address space is wasted. For programs which are slower with 64bit pointers it is a serious problem. You can't really have more then hundert threads in practice. This is not good if you write a server which might want to server 60000 clients with a thread for each one (wait for the 100 core/cpu systems in the near future).

On 64bit systems it's not so serious but it still requires more resources. For example TLB entries for pages are extremely serious for good performance. If you can satisfy 4000 normal thread stackes with one single TLB entry (given a page size of 16MB and 4KB active stack space) you can see the difference. Don't waste 1020KB just for stack that you almost never use.

Small grained multithreading will be a very very important technique in the future.