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Department of Information Technology

UART Publications

Temporal Debugging and Profiling of Multimedia Applications

Lars Albertsson

In Proceedings of Multimedia Computing and Networking 2002, San José, California, USA, January 2002.

Abstract

We present a temporal debugger, capable of examining time flow of applications in general-purpose computer systems. The debugger is attached to a complete system simulator, which models an entire workstation in sufficient detail to run commodity operating systems and workloads. Unlike traditional debuggers, a debugger operating on a simulated system does not disturb the timing of the target program, allowing reproducible experiments and large amounts of instrumentation and monitoring without intrusion. We have implemented the temporal debugger by modifying the GNU debugger to operate on applications in a simulated Linux system. Debugger implementation is difficult because the debugger expects application-related data, whereas the simulator provides low-level data. We introduce a technique, virtual machine translation, for mapping simulator data to the debugger by parsing operating system data structures in the simulated system. The debugger environment allows collection of performance statistics from multiple abstraction levels: hardware, operating system, and application level. We show how this data can be used to profile quality of service performance of a video decoder. The debugger is used to detect display jitter, and by correlating runtime statistics to image rendering time, we expose deviations when the application is unable to render an image in time, thereby locating the cause of the display jitter.

Available as PDF (246 kB)

BibTeX file entry: Albertsson:2002:jan

Updated  2004-02-03 11:30:18 by Zoran Radovic.