Measuring and reducing the impact of the operating system kernel on end-to-end latencies in synchronous packet switched networks
This paper presents an evaluation of the impact of the so-called operating system (OS) latencies on the performance of a synchronous network based on global time coordination. The concept of end-to-end latency was first defined by extending the concept of latency used to evaluate the performance of real-time systems and the end-to-end latency provided by a general-purpose OS was measured as a benchmark. Finally, real-time techniques were used to reduce the worst-case values of such a latency, showing how a gateway between synchronous and asynchronous networks can be implemented by using commercial-off-the-shelf hardware and a proper software stack (based on a real-time version of Linux). The use of a real-time OS is still a nontrivial task, which requires experience and the analysis of the specific application to devise the proper techniques to be applied. This work dissects the problem of OS-to-network data transfer (and vice versa) identifying the key sources of latencies and delay jitter, and solving each problem with the application of a proper technique. Copyright  2011 John Wiley & Sons, Ltd.
kernel latency end-to-end delay pipeline forwarding real-time linux