Offset Pipelined Scheduling: Conditional Branching for CGRAs

Coarse Grained Reconfigurable Arrays (CGRAs) offer improved energy efficiency and performance over conventional architectures. However, modulo counter based control of these devices limits efficiency for applications with multiple execution modes. This work presents a new type of architecture that adds support for branching control flow to CGRAs. The pipelined program counter CGRA framework blends the high parallelism of traditional CGRAs with the flexibility of commodity processors. Offset Pipelined Scheduling (OPS) is the basis of an enhanced CGRA tool chain targeting these devices. OPS is shown to provide an average 1.94x speed up for benchmarks that are resource limited when modulo scheduled.