About unique_ptr performances

Question

I often read that unique_ptr would be preferred in most situations over shared_ptr because unique_ptr is non-copyable and has move semantics; shared_ptr would add an overhead

Answer 1

All you did in the timed blocks is access them. That won't involve any additional overhead at all. The increased time probably comes from the console output scrolling. You can never, ever do I/O in a timed benchmark.

And if you want to test the overhead of ref counting, then actually do some ref counting. How is the increased time for construction, destruction, assignment and other mutating operations of shared_ptr going to factor in to your time at all if you never mutate shared_ptr?

Edit: If there's no I/O then where are the compiler optimizations? They should have nuked the whole thing. Even ideone junked the lot.