Is there a performance penalty for passing “this” by value in Go methods?

Question

I\'m exploring Go after 9 years of C++ development. In C++ it is a bad practice to pass function\'s arguments by value except variables of built-in types because of performa

Answer 1

It depends on the size of the receiver. If the receiver is less than a few dozen bytes, copying it might actually be cheaper than the pointer chasing (extra memory accesses) that would be required if you passed a pointer. Also, using a pointer makes it somewhat more likely that the struct will be allocated on the heap, putting an extra burden on the garbage collector.

In Go, the copy is always a byte-by-byte copy, so the cost depends only on the size of the struct. In C++ it might call a copy constructor, which could potentially take a lot of time.

So, except for really big objects, just use whatever kind of receiver makes the most sense based on the semantics of the method and consistency with the rest of your API.