In complex systems low-level efficiency is far less beneficial than high-level efficiency. To achieve high-level efficiency you need to have a clear understandi

In complex systems low-level efficiency is far less beneficial than high-level efficiency. To achieve high-level efficiency you need to have a clear understanding of how the system works as a whole. That is impossible is the code is unintelligible bag of tricks. I've seen this a lot when working in PHP. I wrote some websites from ground-up (using something similar to my own framework). I optimized int multiple times to great results. The biggest benefits didn't come from making a particular function faster, they came from realizations that large chunks of complexity in templating, routing and permissions checking subsystems simply weren't necessary. It doesn't matter how clever those chunks were written, because I got rid of them completely. I think this is what the author speaks about.