IN-Tune: An In-Situ Non-Invasive Performance Tuning Tool for Multi-threaded Linux on Symmetric Multiprocessing Pentium Workstations

Abstract

This paper documents the design and implementation of the IN-Tune software tool suite, which enables a user to collect real-time code and hardware profiling information on Intel-based symmetric multiprocessors running the Linux operating system. IN-Tune provides a virtually non-invasive tool for performance analysis and tuning of programs. Unlike other analysis tools, IN-Tune isolates data with respect to individual threads. It also utilizes performance monitoring hardware registers to permit instrumentation of individual threads as they run in-situ, thus collecting data with appropriate considerations for a multiprocessor environment. Data can be sampled using two different mechanisms. First, the user can collect data by making calls to the system upon the occurrence of specific software events. Secondly, data can be collected at a fixed, fine grain (e.g. 1-10 microseconds) interval using either software or hardware interrupts. To allow observation of codes for which source code modification is impractical or impossible, a 'shell' task is created which permits monitoring without code modification. Although this work deals with Intel processors and Linux, the widespread availability of performance monitoring registers in modern processors makes this work widely applicable. Copyright © 1999 John Wiley & Sons, Ltd.