2009 Reports

Exploiting Local Logic Structures to Optimize Multi-Core SoC Floorplanning

Li, Cheng-Hong; Sonalka, Sampada; Carloni, Luca

We present a throughput-driven partitioning and a throughput-preserving merging algorithm for the high-level physical synthesis of latency-insensitive (LI) systems. These two algorithms are integrated along with a published floorplanner in a new iterative physical synthesis flow to optimize system throughput and reduce area occupation. The synthesis flow iterates a floorplanning-partitioning-floorplanning-merging sequence of operations to improve the system topology and the physical locations of cores. The partitioning algorithm performs bottom-up clustering of the internal logic of a given IP core to divide it into smaller ones, each of which has no combinational path from input to output and thus is legal for LI-interface encapsulation. Applying this algorithm to cores on critical feedback loops optimizes their length and in turn enables throughput optimization via the subsequent floorplanning. The merging algorithm reduces the number of cores on non-critical loops, lowering the overall area taken by LI interfaces without hurting the system throughput. Experimental results on a large system-on-chip design show a 16.7% speedup in system throughput and a 2.1% reduction in area occupation.