Is gcc std::unordered_map implementation slow? If so - why?

Question

We are developing a highly performance critical software in C++. There we need a concurrent hash map and implemented one. So we wrote a benchmark to figure out, how much slo

Answer 1

I found the reason: it is a Problem of gcc-4.7!!

With gcc-4.7

inserts: 37728
get    : 2985

With gcc-4.6

inserts: 2531
get    : 1565

So std::unordered_map in gcc-4.7 is broken (or my installation, which is an installation of gcc-4.7.0 on Ubuntu - and another installation which is gcc 4.7.1 on debian testing).

I will submit a bug report.. until then: DO NOT use std::unordered_map with gcc 4.7!