When searching for a literal string, the bottleneck tends to be memory bandwidth. When doing regex searches, the bottleneck is usually CPU. If caches are cold,

When searching for a literal string, the bottleneck tends to be memory bandwidth. When doing regex searches, the bottleneck is usually CPU. If caches are cold, then disk I/O is the limiting factor. Even in that case, technologies like NCQ allow some degree of concurrency. If you have ag[1], you can play around with the --workers option to see how various numbers of threads change performance. (The default is for ag to use #CPUs-1 workers.) 1. https://github.com/ggreer/the_silver_searcher https://github.com/ggreer/the_silver_searcher