Determination of Interrupt-Coalescence Latency of Remote Hosts Through Active Measurement

Abstract

Recently, hosts connected to the Internet through network interface cards (NICs) are equipped with a hardware artifact called interrupt coalescence (IC). This artifact reduces the processing load of a host in exchange for an additional delay in the receiving of packets that arrive into its NIC. Even though the adoption of IC has its benefits, the additional delay negatively affects the hosts that are involved in the performance measurement of various network parameters and time-sensitive applications. Therefore, prior knowledge of IC-inflicted delay may be used to facilitate accurate delay and bandwidth measurements, IP geolocation, and traffic load-balancing. In this paper, we propose what we believe as the first scheme to measure the IC period (the additional delay) of remote hosts through the use of pairs of probing packets and a k-means clustering algorithm. We report the practicability of our scheme and the high accuracy through extensive experiments on both controlled and production networks consisting of up to 1000-Mb/s links. Our experimental evaluations show that the proposed scheme measures IC period with 90% accuracy, quickly, and with a small probing load.