SlideAcross: A Low-Latency Adaptive Router for Chip Multi-processor

Abstract

The non-uniform distributed traffic of chip multi-processor (CMP) demands an on-chip communication infrastructure which is able to avoid congestion under high traffic conditions while possessing minimal pipeline delay at low load conditions. In this paper, we propose a low-latency adaptive router with a low-complexity single-cycle bypassing mechanism to meet the communication needs of CMPs. At low loads, this router transmits a flit using dimension-ordered routing (DoR) in the bypass datapath. When the output port required intra-dimension bypassing is not available, the packet is routed adaptively to avoid congestion. The router also has a simplified virtual channel allocation (VA) scheme that yields a non-speculative low-latency pipeline. By combining the low-complexity bypassing technique together with adaptive routing, the proposed router architecture can achieve low-latency communication under various traffic loads. Simulation shows that proposed router can reduce applications' execution time by 16.9% in average compared to low-latency router SWIFT.