A GPU based real-time software correlation system for the Murchison Widefield Array prototype

TL;DR

This paper presents a GPU-based real-time digital correlator for radio astronomy, demonstrating significant performance improvements over CPU implementations and enabling cost-effective, high-performance correlation on standard PC hardware.

Contribution

The paper introduces a GPU-accelerated correlator implementation using NVIDIA CUDA, optimized for radio astronomy, achieving high performance and real-time operation on commodity hardware.

Findings

GPU correlator outperforms CPU by a factor of 60 for 32 antennas

Achieves real-time correlation on standard PC hardware

Optimized design minimizes global memory reads for better performance

Abstract

Modern graphics processing units (GPUs) are inexpensive commodity hardware that offer Tflop/s theoretical computing capacity. GPUs are well suited to many compute-intensive tasks including digital signal processing. We describe the implementation and performance of a GPU-based digital correlator for radio astronomy. The correlator is implemented using the NVIDIA CUDA development environment. We evaluate three design options on two generations of NVIDIA hardware. The different designs utilize the internal registers, shared memory and multiprocessors in different ways. We find that optimal performance is achieved with the design that minimizes global memory reads on recent generations of hardware. The GPU-based correlator outperforms a single-threaded CPU equivalent by a factor of 60 for a 32 antenna array, and runs on commodity PC hardware. The extra compute capability provided by the GPU maximises the correlation capability of a PC while retaining the fast development time associated with using standard hardware, networking and programming languages. In this way, a GPU-based correlation system represents a middle ground in design space between high performance, custom built hardware and pure CPU-based software correlation. The correlator was deployed at the Murchison Widefield Array 32 antenna prototype system where it ran in real-time for extended periods. We briefly describe the data capture, streaming and correlation system for the prototype array.