Thread: C++ Explict Dynamic Memory Allocation - Why?

Originally Posted by grumpy

The distinction between heap and stack - and any performance benefits of using one or the other - has been minimal or non-existent with modern operating systems since the mid 1990s

I don't see how they could possibly have eliminated the copying penalty at the operating system level. the only way I can think of is to use the x86 paging mechanism and copy-on-write, but that would give application code a lot of low level access to kernel-space things.

Originally Posted by grumpy

My comment that you quoted concerned different performance (or lack thereof in modern systems) offered by heap and stack, not on the overhead of copying objects.

any system that accesses memory as a contiguous block will have no penalty for heap versus stack access.

While it is true that modern operating systems impose address quotas on processes, the quotas are usually much larger than 1MB.

as an example, the default stack size for a win32 thread is 1MB, if you specify 0 for stack size when calling CreateThread(). since you cannot always be sure you are not running in a child thread (without explicitly checking for it), it's not unreasonable to expect that you might need to plan for this situation.