Valgrind

• valgrind <your-program> <args> : memory checker
• valgrind –db-attach=yes <your-program> <args> : to automatically attach gdb on errors
• valgrind –leak-check=full <program> <args> : to completely analyse memory leaks
• valgrind –tool=massif –time-unit=B <program> <args> + ms_print massif.<pid> : statistics about which functions are using memory
• valgrind –tool=callgrind <program-compiled-O2> <args> + kcachegrind callgrind.out.xxxx + calgrind_control : call profiling
• valgrind –tool=cachegrind <program-compiled-O2> <args> : CPU cache profiling in order to find cache misses

Always do profiling with optimization options of compiler, or you could optimize things that the compiler already automatically does.