Routability-Enhanced Scheduling for Application Mapping on CGRAs

Abstract

Coarse-Grained Reconfigurable Architectures (CGRAs) are a promising solution to domain-specific applications for their energy efficiency and flexibility. To improve performance on CGRA, modulo scheduling is commonly adopted on Data Dependence Graph (DDG) of loops by minimizing the Initiation Interval (II) between adjacent loop iterations. The mapping process usually consists of scheduling and placement-and-routing (P&R). As existing approaches don’t fully and globally explore the routing strategies of the long dependencies in a DDG at the scheduling stage, the following P&R is prone to failure leading to performance loss. To this end, this paper proposes a routability-enhanced scheduling for CGRA mapping using Integer Linear Programming (ILP) formulation, where a global optimized scheduling could be found to improve the success rate of P&R. Experimental results show that our approach achieves $1.12\times $ and $1.22\times $ performance speedup, 28.7% and 50.2% compilation time reduction, as compared to 2 state-of-the-art heuristics.

Keywords

• Coarse-grained reconfigurable architectures (CGRAs)
• modulo scheduling
• routing strategy
• placement and routing (P&R)