Performance profiling on Linux

Question

What are the best tools for profiling C/C++ applications on *nix?

(I\'m hoping to profile a server that is a mix of (blocking) file IO, epoll for network and fork()/

Answer 1

Allinea MAP is a profiler for C++ and other native languages on Linux. It is commercially supported by my employer. It has a graphical interface and source-line level profiling and profiles code with almost no slowdown which makes it very accurate where timing of other subsystems is relevant - such as for IO.

Callgrind has been useful and accurate - but the slowdown was ~5x so I could only do smaller runs. It can actually count the number of times a function is called which is useful for understanding asymptotic behavior.