Multivoltage scheduling with voltage-partitioned variable storage

Multivoltage scheduling (MVS) for datapaths offers the energy savings of voltage scaling on a per-operation basis with a voltage aware operator scheduling. This work investigates the effect of using multivoltage register file storage in operator graph scheduling for multivoltage datapaths, thus partitioning the variable storage space on the basis of operating voltages. Scheduling operations on multivoltage functional units lowers the energy-delay product by exploiting slack in the schedule. We find that using multivoltage partitioned register files do the same by exploiting the variable lifetimes in the schedule. In a resource constrained context, longer variable lifetimes provide the opportunity to store such variables in low voltage register files. A ZOLP formulation for the resource constrained MVS problem is presented along with energy-delay savings obtained from applying this formulation to image processing transform graphs.