Operating-system level tracing tools for the DEC AXP architecture

Trace-driven simulation is commonly used by the computer architecture community to answer a wide range of design questions. Traces taken from benchmark program execution (commonly from the SPEC95 suite) have been used extensively to study instruction scheduling, branch prediction, and cache design. Today's computer designs have been optimized based on the workload characteristics of these benchmarks. One important issue which has been ignored in these traces is the lack of operating system activity. It has been acknowledged by a number of researchers that operating system interaction can severely affect the validity of any trace-driven simulation study. The major reason why most studies have elected to ignore this fact is due to the difficulty of obtaining such traces. In this contribution we describe two tools which have been developed at Digital Equipment Corporation, in collaboration with Northeastern University's Computer Architecture Research Laboratory, which capture operating-system rich traces. These tools can be used for capturing trace information on an DEC Alpha-based system, running either the DEC Unix or Microsoft Windows NT operating system.