Simultaneous Multithreading: Maximizing On-Chip Parallelism

This paper examines simultaneous multithreading, a technique permitting several independent threads to issue instructions to a superscalar's multiple functional units in a single cycle. We present several models of simultaneous multithreading and compare them with alternative organizations: a wide superscalar, a fine-grain multithreaded processor, and single-chip, multiple-issue multiprocessing architectures. Our results show that both (single-threaded) superscalar and fine-grain multithreaded architectures are limited in their ability to utilize the resources of a wide-issue processor. Simultaneous multithreading has the potential to achieve 4 times the throughput of a superscalar, and double that of fine-grain multithreading. We evaluate several cache configurations made possible by this type of organization and evaluate tradeoffs between them. We also show that simultaneousmultithreading is an attractive alternative to single-chip multiprocessors; simultaneous multithreaded pr...

• Type: Conference
• Year: 1998
• Where: ISCA
• Authors: Dean M. Tullsen, Susan J. Eggers, Henry M. Levy
• Keywords: Alternative Organizations, Fine-grain Multithreaded Processor, Hardware, ISCA 1998, Simultaneous Multithreading