The article delves into the magic of CPU performance optimization through value speculation, a trick that utilizes the branch predictor to guess values, increasing instruction parallelism and eliminating bottlenecks in the L1 cache. The author, Per Vognsen, references a blog post by Paul Khuong and explores the impact of this trick on summing linked lists, providing real-world examples and performance comparisons. Surprisingly, compilers such as gcc and clang can undo this optimization, prompting manual tweaking of the code for improved efficiency. Ultimately, the article highlights the fascinating interplay between hardware capabilities, software implementation, and performance outcomes.
https://mazzo.li/posts/value-speculation.html