This ignores the rule of thumb that 90% of CPU time is spent in 10% of the code. It is completely pointless to optimize most high-level glue logic, for instance

This ignores the rule of thumb that 90% of CPU time is spent in 10% of the code. It is completely pointless to optimize most high-level glue logic, for instance: even making it run 10x faster produces insignificant performance and power savings.