Mailing the story:
This week at LWN: The problem with prefetch
Over time, software developers tend to learn that micro-optimization efforts are generally not worthwhile, especially in the absence of hard data pointing out a specific problem. Performance problems are often not where we think they are, so undirected attempts to tweak things to make them go faster can be entirely ineffective. Or, indeed, they can make things worse. That is a lesson that the kernel developers have just relearned.