Diagnosing Performance Changes by Comparing System Behaviours
CARNEGIE-MELLON UNIV PITTSBURGH PA PARALLEL DATA LABORATORY
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The causes of performance changes in a distributed system often elude even its developers. This paper develops a new technique for gaining insight into such changes comparing system behaviours from two executions e.g., of two system versions or time periods. Building on end-to-end request flow tracing within and across components, algorithms are described for identifying and ranking changes in the flow andor timing of request processing. The implementation of these algorithms in a tool called Spectroscope is described and evaluated. Five case studies are presented of using Spectroscope to diagnose performance changes in a distributed storage system caused by code changes and configuration modifications, demonstrating the value and efficacy of comparing system behaviours.
- Computer Systems