Advance Virtual Channel Reservation
Boqian Wang1,2,a and Zhonghai Lu1,b
1KTH Royal Institute of Technology National University of Defense Techonology
2School of Electrical Engineering and Computer Science KTH Royal Institute of Technology
aboqian@kth.se
bzhonghai@kth.se
ABSTRACT
We present a smart communication service called Advance Virtual Channel Reservation (AVCR) to provide a highway to packets, which can greatly reduce their contention delay in NoC. AVCR takes advantage of the fact that we can know or predict the destination of some packets ahead at the network interface (NI). Exploiting the time slack before a packet is ready, AVCR establishes an end-to-end highway from the source NI to the destination NI. This highway is built up by reserving virtual channel (VC) resources ahead and at the same time, offering priority service to those VCs in the router, which can therefore avoid highway packets’ VC allocation and switch arbitration delay in NoC. Additionally, optimization schemes are developed to reduce VC overhead and increase highway utilization. We evaluate AVCR with cycle-accurate full-system simulations in GEM5 by using all benchmarks in PARSEC. Compared to the state-of-art mechanisms and the priority based mechanism, experimental results show that our mechanism can significantly reduce the target packets’ transfer latency and effectively decrease the average region-of-interest (ROI) time by 22.4% (maximally by 29.4%) across PARSEC benchmarks.
