Dueling performance monitors

Contemporary processors provide performance monitoring units which can be used to count low-level events like instruction execution, cache misses, branch predictions, and so on. While there have been out-of-tree performance monitoring patches for years, the mainline Linux kernel has never fully supported access to low-level performance counters. Now, suddenly, there are two competing patches which provide this support. This article (from this week's Kernel Page, subscribers only) looks at the two differing approaches to performance monitoring.

Full Story (comments: 25)