An Evaluation of Per-Chip Nonuniform Frequency Scaling on Multicores Xiao Zhang, Kai Shen, Sandhya Dwarkadas, and Rongrong Zhong Department of Computer Science, University of Rochester Concurrently running applications on multiprocessors may desire different CPU frequency/voltage settings in order to achieve performance, power, or thermal objectives. Today's multicores typically require that all sibling cores on a single chip run at the same frequency/voltage level while different CPU chips can have non-uniform settings. This paper targets multicore-based symmetric platforms and demonstrates the benefits of per-chip adaptive frequency scaling on multicores. Specifically, by grouping applications with similar frequency-to-performance effects, we create the opportunity for setting a chip-wide desirable frequency level. We run experiments with 12 SPECCPU2000 benchmarks and two server-style applications on a machine with two dual-core Intel ``Woodcrest'' processors. Results show that per-chip frequency scaling can save ~20 watts of CPU power while maintaining performance within a specified bound of the original system.