Initial observations of the simultaneous multithreading Pentium 4 processor

We analyze an Intel Pentium 4 hyper-threading processor. The focus is to understand its performance and the underlying reasons behind that performance. Particular attention is paid to putting the processor in context with prior published research in simultaneous multithreading-validating and reevaluating, where appropriate, how this processor performs relative to expectations. Results include multiprogrammed speedup, parallel speedup, as well as synchronization and communication throughput. The processor is also evaluated in the context of prior work on the interaction of multithreading with the operating system and compilation.