Power consumption reduction in MPSoCs through DFS

The use of power management techniques is mandatory in embedded devices, which must provide high performance with low energy consumption. Due to the high variability present in the applications workload executed by these devices, this management should be executed dynamically. The use of traditional dynamic voltage and frequency scaling (DVFS) techniques proved to be useful in several scenarios to save energy. Nonetheless, due to technology scaling that limits the voltage variation and slow response of the DVFS schemes, the use of such technique may become inadequate. As alternative, the use of dynamic frequency scaling (DFS) may provide a good trade-off between power savings and power overhead. This paper proposes a distributed DFS scheme for NoC-based MPSoCs. Both NoC and PEs have an individual controlling scheme. The DFS scheme for PEs takes into account its computation and communication load to dynamically change the operating frequency. In the NoC, the DFS controller uses packet information to decide the router operating frequency. Real and synthetic applications were used to evaluate the proposed scheme. Results show that the number of executed instructions is reduced up to 41%, with an execution time overhead up to 18%. The power dissipation is reduced in PEs up to 26% and in the NoC up to 76%.