Chapter 3 - Multi-core Processors and Embedded

Abstract

Multicore processor implies two or more processor cores in the same physical package. Multicore processors differ from multiprocessor systems physically and differ on a number of characteristics: communication latency, bandwidth, and number of processors. The communication latency of a multicore processor is typically lower than a multiprocessor. Bandwidth between cores of a multicore processor is also typically higher than a multiprocessor. The reason is the proximity of the processor cores. The current multicore IA-32 architecture processors have a maximum of four cores in a package. The expectation is the number of cores made available in multicore processors will increase over successive generations; however, there are some fundamental hardware and software challenges that will need to be solved before large-scale multicore processors become practical. One classification of multicore processors is based upon the type of processor cores in the package. A homogeneous multicore processor is composed of processor cores that support the same instruction set architecture (ISA). A heterogeneous multicore processor is composed of processor cores that support different ISAs. A heterogeneous multicore processor has the advantage of employing specialized processor cores designed for the task.