Gathering and using time measurements in distributed systems
Margaret A. Dietz, Carla Schlatter Ellis · 1996
It is often necessary to measure time in distributed computer systems. For example, timestamps are used for measuring the intervals between events (like banking transactions). They are also used for ordering events, as in the generation of transaction logs and debug traces. Perhaps their most common use is in performance evaluation, capacity planning, and the detection of unpredicted delays or bottlenecks. Measuring and using time in a distributed environment presents some unique challenges. This thesis illuminates these problems and presents techniques for the proper measurement and use of time. The first challenge is the clocks themselves. Chapter 3 describes the tradeoff between keeping clocks synchronized and keeping them accurate. The inaccuracies of networked workstation clocks are examined, and two statistical techniques are described for collecting time measurements in spite of these insufficiencies. The second challenge is synchronization. There is often a need to order eve...