# Understanding Software Dynamics

Dick Sites (DEC Alpha co-architect, later Google) on observing what software actually does on a real machine: CPU, memory, disk, network, locks, queues. The book is built around KUtrace, Sites's own low-overhead kernel/user tracer, and the working assumption is that traditional sampling profilers lie about the 99th percentile. Read by the [[eatonphil-bookclub]] in 2024: [cohort page](https://eatonphil.com/2024-understanding-software-dynamics.html).

Related concepts: [[gpu-accelerated-terminal]] (different domain but same "measure, don't guess" frame), [[spinlock]].