Amdahl's law in the multicore era

Computing vendors' road maps promise multiple processor cores that will double the number of cores per chip repeatedly. Yet designers must subdue more degrees of freedom for multicore chips than for single-core designs. Amdahl's law shows that this model has important consequences for the multicore era. Sources as varied as Intel and the University of California, Berkeley, predict designs of a hundred, if not a thousand, cores. The authors offer a corollary of a simple model of multicore hardware resources. Their results should encourage multicore designers to view the entire chip's performance rather than focusing on core efficiencies. They also describe several important limitations of their models to stimulate discussion and future work.