A FAST AND FAIR SHARED BUFFER FOR HIGH-RADIX ROUTER

Abstract

High-radix router based on the tile structure requires large amount of buffer resources. To reduce the buffer space requirement without degrading the throughput of the router, shared buffer management schemes like dynamically allocated multi-queue (DAMQ) can be used by improving the buffer utilization. Unfortunately, it is commonly regarded that DAMQ is slow in write and read. To address this issue, we propose a fast and fair DAMQ structure called F2DAMQ for high-radix routers in this paper. It uses a fast FIFO structure in the implementation of idle address list as well as data buffer and achieves some critical performance improvement such as continuous and concurrent write and read with zero-delay. Besides, F2DAMQ also uses a novel credit management mechanism which is efficient in avoiding one virtual channel (VC) monopolizing the shared part of the buffer and achieving fairness among competing VCs sharing the buffer. The analyses and simulations show that F2DAMQ performs well in achieving low latency, high throughput and good fairness under different traffic patterns.