Near Theoretical Gigabit Link Efficiency for Distributed Data Acquisition Systems

Link efficiency, data integrity, and continuity for high-throughput and real-time systems are crucial. Most of these applications require specialized hardware and operating systems (OSs) as well as extensive tuning in order to achieve high efficiency. Here, we present an implementation of gigabit ethernet data streaming, which can achieve 99.26% link efficiency while maintaining no packet losses. The design and implementation are built on OpenPET, an opensource data acquisition platform for nuclear medical imaging, where: 1) a crate hosting multiple OpenPET detector boards uses a user datagram protocol over Internet protocol ethernet soft-core, which is capable of understanding PAUSE frames, to stream data out to a computer workstation; 2) the receiving computer uses Netmap to allow the processing software (i.e., user space), which is written in Python, to directly receive and manage the network card's ring buffers, bypassing the OS kernel's networking stack; and 3) a multithreaded application using synchronized queues is implemented in the processing software (Python) to free up the ring buffers as quickly as possible while preserving data integrity and flow continuity.