Profiling C++

Use gprof:
Add -pg to compiler and linker flags and rebuild.
Call the program to collect profiling info.
Call the program with gprof yourprogram to see profiling info.

Use valgrind with the following options

valgrind --tool=callgrind ./(Your binary)

It will generate a file called callgrind.out.x. You can then use kcachegrind tool to read this file. It will give you a graphical analysis of things with results like which lines cost how much.