Proceedings 2001 International Conference on Parallel Architectures and Compilation Techniques (2001)
Sept. 8, 2001 to Sept. 12, 2001
James Burns , Intel
Jean-Luc Gaudiot , University of Southern California
Abstract: Two approaches to high throughput processors are Chip Multi-Processing (CMP) and Simultaneous Multi-Threading (SMT). CMP increases layout efficiency, which allows more functional units and a faster clock rate. However, CMP suffers from hardware partitioning of functional resources. SMT increases functional unit utilization by issuing instructions simultaneously from multiple threads. However, a wide-issue SMT suffers from layout and technology implementation problems. We use silicon resources as our basis for comparison and find that area and system clock have a large effect on the optimal SMT/CMP design trade. We show the area overhead of SMT on each processor and how it scales with the width of the processor pipeline and the number of SMT threads. The wide issue SMT delivers the highest single-thread performance with improved multi-thread throughput. However multiple smaller cores deliver the highest throughput.
J. Gaudiot and J. Burns, "Area and System Clock Effects on SMT/CMP Processors," Proceedings 2001 International Conference on Parallel Architectures and Compilation Techniques(PACT), Barcelona, Spain, 2001, pp. 0211.