Valgrind is a suite of tools for profiling software:

Memcheck detects memory issues (leaks, accessing invalid memory, deallocating memory more than once, etc.)
Cachegrind profiles CPU cache misses, a possible optimization opportunity
Callgrind is an extension to Cachegrind with more information
Massif profiles memory heaps for performance issues
Helgrind detects multithreading race conditions

Valgrind

See also