Updated: Jan 06, 2020 by Pradeep Gowda.
Tagged: programming

The Fallacy of Premature Optimization

Every programmer with a few years’ experience or education has heard the phrase “premature optimization is the root of all evil.” This famous quote by Sir Tony Hoare (popularized by Donald Knuth) has become a best practice among software engineers. Unfortunately, as with many ideas that grow to legendary status, the original meaning of this statement has been all but lost and today’s software engineers apply this saying differently from its original intent.

The full version of the quote is “We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.” and I agree with this. Its usually not worth spending a lot of time micro-optimizing code before its obvious where the performance bottlenecks are. But, conversely, when designing software at a system level, performance issues should always be considered from the beginning. A good software developer will do this automatically, having developed a feel for where performance issues will cause problems. An inexperienced developer will not bother, misguidedly believing that a bit of fine tuning at a later stage will fix any problems.