Network topology plays a vital role in chip design, it largely determines network cost (power and area) and significantly impacts communication performance in many-core architectures. Conventional topologies such as a 2D mesh have drawbacks including high diameter as the network scales and poor load balancing for the center nodes. We propose a methodology to design random topologies for on-chip networks. Random topologies provide better scalability in terms of network diameter and provide inherent load balancing. As a proof-of-concept for random on-chip topologies, we explore a novel set of networks -- do decs -- and illustrate how they reduce network diameter with randomized low-radix router connections. While a 4 × 4 mesh has a diameter of 6, our dodec has a diameter of 4 with lower cost. By introducing randomness, dodec networks exhibit more uniform message latency. By using low-radix routers, dodec networks simplify the router micro architecture and attain 20% area and 22% power reduction compared to mesh routers while delivering the same overall application performance for PARSEC.

The 3780-point FFT is a main component of the time domain synchronous OFDM (TDS-OFDM) system in the Chinese Digital Terrestrial Multimedia Broadcasting (DTMB) national standard. In this paper, we proposed a pure software solution for the 3780-point FFT on a multi-core processor to achieve high performance and high flexibility. A new 12-point FFT implementation is used to improve system performance significantly since it is one of the key modules in 3780-point FFT. Together with some other techniques such as optimized assembly code, this 3780-point FFT improves the throughput by 39.26% and reduces the number of instructions by 19.9% compared with the non-optimized method. The throughput achieves 13.595 Msamples/s and meets the requirement of DMBT standard.