C++ map vs map performance (I know, “again?”)

Question

I was using a map with a std::string key and while everything was working fine I wasn\'t getting the performance I expected. I searched for places to optimize

Answer 1

If your in C++ 11, the copy constructor is not called unless the string is changed. Because std::string is a C++ construct, at least 1 dereference is needed to get at the string data.

My guess would be the time is taken up in an extra dereference (which if done 10000 times is costly), and std::string is likely doing appropriate null pointer checks, which again eats up cycles.