ATUM: A NEW TECHNIQUE FOR CAPTURING ADDRESS TRACES USING MICROCODE.

Abstract

Trace-driven simulation is often used in the design of computer systems, especially caches and translation lookaside buffers. Capturing address traces to drive such simulation has been problematic, often involving 1000:1 software overhead to trace a target workload, and/or mechanisms that cause significant distortions in the recorded data. A new technique for capturing address traces has been developed. Called Addressed Trace Using Microcode (ATUM), it uses a processor's microcode to record addresses in a reserved part of main memory as a side effect of normal execution. An experimental implementation of this technique on a VAX 8200 processor shows a number of advantages over previous techniques, including fewer distortions of the address trace and a hundred times faster recording. With this technique, it is possible to gather full operating-system traces of multitasking workloads.