Performance tuning is some of the hardest software you will do.
Always try to test your system with as much fidelity as possible.
And allow multiple levels of simulation.Before you ship, measure how much spare performance you have
Leave most of the debugging in the “test” release to slow system down.Common fixes to performance cause other problems
Caching – uses more memoryLooping – increases latency
Do performance fixes First & Last
i.e. design for performance, code for maintainabilityDebug for performance only if you must.