Linus Torvalds (if I remember correctly) points out that there is no reason to optimize code beyond the point that the user cannot see the difference in perform

Linus Torvalds (if I remember correctly) points out that there is no reason to optimize code beyond the point that the user cannot see the difference in performance. It makes sense that if I click a button, and whatever that button is meant to do takes place apparently instantaneously, there is no point to making the code any faster. However it is worthwhile to consider the effect of one's code on energy consumption as well as the performance of other parts of the system, generation of waste heat &c.