Real-Time power management for a multi-performance processor

This paper presents an energy efficient embedded processor which can be used as a design alternative for the dynamic voltage scaling (DVS) processors in embedded real-time system design. The processor consists of multiple same-ISA PE (processing element) cores and a selective set-associative cache memory. The PE-cores differ in their clock speeds and energy consumptions. Only a single PE-core is activated at a time and the other PE-cores are deactivated using clock gating and signal gating. The major advantage over the DVS processors is a small overhead for changing its performance. Our processor can change its performance within 1.5 microsecond and dissipates about 10 nano-joule while conventional DVS processors need hundreds of microseconds and dissipate a few micro-joule for each voltage transition. Our processor makes it possible to use the DVS control in embedded real-time systems and to perform more sophisticated dynamic power management.