Floorplan driven leakage power aware IP-based SoC design space exploration

Abstract

Multi-million gate system-on-chip (SoC) designs increasingly rely on intellectual property (IP) blocks. However, due to technology scaling the leakage power consumption of the IP blocks has risen thus leading to possible thermal runaway. In IP-based design there has been a disconnect between system level design and physical level steps such as floorplanning which can lead to failures in manufactured chips. This necessitates coupling between system level and physical level design steps. The leakage power of an IP-block increases with its temperature which is dependent on the SoC's floorplan due to thermal diffusion. We have observed that different floorplans of the same SoC can have up to 3X difference in leakage power. Hence the system designer needs to be aware of this design space between floorplans and leakage power. We propose a leakage aware exploration (LAX) framework which enables the system designer to create this design space early in the design cycle and provides an opportunity to make changes in the system design. We show the size of the design space generated by applying LAX on ten industrial SoC designs from Freescale Semiconductor Inc. and observe that the leakage power can vary by as much as 190% for 65% difference in the inactive area.