Improving interactive performance using TIPME

On the vast majority of today's computers, the dominant form of computation is GUI-based user interaction. In such an environment, the user's perception is the final arbiter of performance. Human-factors research shows that a user's perception of performance is affected by unexpectedly long delays. However, most performance-tuning techniques currently rely on throughput-sensitive benchmarks. While these techniques improve the average performance of the system, they do little to detect or eliminate response-time variabilities—in particular, unexpectedly long delays. We introduce a measurement infrastructure that allows us to improve user-perceived performance by helping us to identify and eliminate the causes of the unexpected long response times that users find unacceptable. We describe TIPME (The Interactive Performance Monitoring Environment), a collection of measurement tools that allowed us to quickly and easily diagnose interactive performance “bugs” in a mature operating system. We present two case studies that demonstrate the effectiveness of our measurement infrastructure. Each of the performance problems we identify drastically affects variability in response time in a mature system, demonstrating that current tuning techniques do not address this class of performance problems.