Re-evaluating Measurement Algorithms in Software.

With the advancement of multicore servers, there is a new trend of moving network functions to software servers. Measurement is critical to most network functions as it not only helps the operators understand the network usage and detect anomalies, but also produces feedback to the control loop in management tasks such as load balancing and traffic engineering. Traditional researches on measurement algorithms mainly focus on reducing the memory usage leveraging the fact that measurement can sustain bounded inaccuracy. In this study, we re-evaluate these algorithms on software servers in order to understand their tradeoffs of accuracy and performance. We observe that simple hash tables work better than more advanced measurement algorithms for a variety of measurement scenarios. This is because with better cache design in modern servers and the skewness in the access patterns of measurement tasks, the memory usage of measurement tasks is largely irrelevant to the packet processing performance.