π€ AI Summary
This work addresses the computational bottleneck in quantum error correction decoding, which severely limits the practicality of fault-tolerant quantum computers. We present the first systematic low-level performance optimization of the Tesseract decoder, introducing the A* search algorithm to efficiently traverse the exponentially large error hypothesis graph. This approach is further enhanced by optimized data structures, restructured memory layouts to improve cache locality, and hardware-accelerated bitwise operations. Our optimizations yield approximately 2Γ speedup on both Color Codes and Surface Codes, and over 5Γ acceleration on Bivariate-Bicycle Codes, significantly improving the decoderβs scalability and practical applicability for real-world quantum computing systems.
π Abstract
Quantum Error Correction (QEC) is essential for building robust, fault-tolerant quantum computers; however, the decoding process often presents a significant computational bottleneck. Tesseract is a novel Most-Likely-Error (MLE) decoder for QEC that employs the A* search algorithm to explore an exponentially large graph of error hypotheses, achieving high decoding speed and accuracy. This paper presents a systematic approach to optimizing the Tesseract decoder through low-level performance enhancements. Based on extensive profiling, we implemented four targeted optimization strategies, including the replacement of inefficient data structures, reorganization of memory layouts to improve cache hit rates, and the use of hardware-accelerated bit-wise operations. We achieved significant decoding speedups across a wide range of code families and configurations, including Color Codes, Bivariate-Bicycle Codes, Surface Codes, and Transversal CNOT Protocols. Our results demonstrate consistent speedups of approximately 2x for most code families, often exceeding 2.5x. Notably, we achieved a peak performance gain of over 5x for the most computationally demanding configurations of Bivariate-Bicycle Codes. These improvements make the Tesseract decoder more efficient and scalable, serving as a practical case study that highlights the importance of high-performance software engineering in QEC and providing a strong foundation for future research.