Cygnus: A 1 GHz Heterogeneous Octa-Core RISC-V Vector Processor for DSP

We introduce Cygnus, an energy-efficient octa-core RISC-V vector processor compliant with the RVV 1.0 specification targeting digital signal processing (DSP) applications. This chiplet features dynamic instruction scheduling with short vector lengths at the vector core level and a big/little architecture with tightly-coupled memory at the SoC level, facilitating efficient streaming data flow across cores. Cygnus demonstrates a high average utilization of 90% across GEMM and CONV kernels, achieving leading energy efficiencies of 414 GOPS/W for INT8 GEMM and 109 GFLOPS/W for FP32 GEMM. In a representative computer vision kernel implementing denoising using a non-local means algorithm, the chiplet delivers a latency of 3.7 ms with an energy consumption of 518 μJ/ frame.