Not sure why this was downvoted. Optimization can involve every layer of the stack from high level software architecture and cloud systems down to worrying about false dependency for lzcnt instruction on Haswell CPUs. Most jobs will only involve a small part of this, so the question, as it is written, lacks context.
I guess there are some common parts like profiling and statistics, but thats about it.
I guess there are some common parts like profiling and statistics, but thats about it.