Check out the new USENIX Web site.

USENIX, The Advanced Computing Systems Association

NSDI '06 — Abstract

Pp. 115–128 of the Proceedings

Pip: Detecting the Unexpected in Distributed Systems

Patrick Reynolds, Duke University; Charles Killian, University of California, San Diego; Janet L. Wiener, Jeffrey C. Mogul, and Mehul A. Shah, Hewlett-Packard Laboratories, Palo Alto; Amin Vahdat, University of California, San Diego


Bugs in distributed systems are often hard to find. Many bugs reflect discrepancies between a system's behavior and the programmer's assumptions about that behavior. We present Pip, an infrastructure for comparing actual behavior and expected behavior to expose structural errors and performance problems in distributed systems. Pip allows programmers to express, in a declarative language, expectations about the system's communications structure, timing, and resource consumption. Pip includes system instrumentation and annotation tools to log actual system behavior, and visualization and query tools for exploring expected and unexpected behavior. Pip allows a developer to quickly understand and debug both familiar and unfamiliar systems.

We applied Pip to several applications, including FAB, SplitStream, Bullet, and RanSub. We generated most of the instrumentation for all four applications automatically. We found the needed expectations easy to write, starting in each case with automatically generated expectations. Pip found unexpected behavior in each application, and helped to isolate the causes of poor performance and incorrect behavior.

  • View the full text of this paper in HTML and PDF. Listen to the presentation in MP3 format.
    Click here if you have forgotten your password Until May 2007, you will need your USENIX membership identification in order to access the full papers. The Proceedings are published as a collective work, © 2006 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.

  • If you need the latest Adobe Acrobat Reader, you can download it from Adobe's site.
To become a USENIX Member, please see our Membership Information.

Last changed: 1 June 2006 ch