Why a Stack?
Allocating memory on the stack is preferred when possible because the stack is faster and simpler than the heap (which we'll get to, be patient):
- Efficient Pointer Management: Stack "allocation" is just a quick increment or decrement of the stack pointer, which is extremely fast. Heap allocations require more complex bookkeeping.
- Cache-Friendly Memory Access: Stack memory is stored in a contiguous block, enhancing cache performance due to spatial locality. Related values live next to each other in memory, the CPU can load and access them more quickly.
- Automatic Memory Management: Stack memory is managed automatically as functions are called and as they return.
- Inherent Thread Safety: Each thread has its own stack. Heap allocations require synchronization mechanisms when used concurrently, potentially introducing overhead.
One reason Go programs are efficient is that Go uses stack allocation for variables when possible, much like C. The Go compiler performs escape analysis to decide whether a variable can be allocated on the stack. On the other hand, languages like Python allocate most objects on the heap, which can impact performance.