SuperCore: An Ultra-Fast Superconducting Processor for Cryogenic Applications

Superconductor single-flux-quantum (SFQ) logic family has been recognized as a promising technology for cryogenic applications (e.g., quantum computing, astronomy, metrology) thanks to its ultra-fast and low-energy characteristics. Therefore, recent efforts in SFQ-based computing have focused on developing fast and low-power SFQ processors for cryogenic applications. However, there still has been little progress toward a convincing SFQ processor design due to the critical performance challenges originating from its extremely deep pipeline. In this paper, we propose a super-fast and low-power in-order SFQ processor by tackling the challenges from the deep pipeline. First, we develop a minimal-depth SFQ processor pipeline with novel architecture-level ideas. Next, we conduct in-depth performance analyses and identify three real performance bottlenecks in the deeply pipelined SFQ processors (i.e., stall/flush logic, RAW stall, fetch unit). Finally, we propose SuperCore, our super-fast SFQ-based processor architecture, with three SFQ-friendly solutions that effectively resolve the identified bottlenecks. With our solutions applied, SuperCore achieves 11 times speed-up over the SFQ processor baseline. In addition, SuperCore achieves six times speed-up and consumes up to 193 times less power compared to in-order CMOS processors running at 4K.