System-Level Power Estimation with On-Chip Bus Performance Monitoring Units in PKU-DSPII SoC

Runtime system-level power estimation is essential for dynamic power adaptation in integrated circuits. Indirect power estimation using a CPU performance monitoring unit (PMU) is widely used in modern microprocessors for its low cost. However, the existing CPU PMUs only monitor the activities of core and cache, resulting in accuracy limitation in power estimation for systems containing heterogeneous devices. In this paper, an on-chip bus PMU (OCB PMU) is proposed for PKU-DSPII SOC to achieve accurate system-level power estimation by taking range of peripheral devices into account. By monitoring the on-chip bus signals which indicate almost all the information of the system behavior, an OCB PMU is able to recognize different types of devices. By imitating the internal behavior of every device triggered by OCB signals using an energy state machine (ESM), an OCB PMU is capable of accurate power estimation of heterogeneous devices with complicated behavior. The proposed PMUs can also flexibly adapt to different SoC architectures.