Experimental performance evaluation of a hybrid packet reception scheme for Linux networking subsystem

The heavy traffic introduced by Gigabit networks can result in a significant performance degradation of network hosts. This degradation happens as a result of the interrupt overhead associated with the high rate of packet arrivals. NAPI, a packet reception mechanism integrated into the latest version of Linux networking subsystem, was designed to improve Linux performance to suit today´s Gigabit traffic. NAPI is definitely a major step up from earlier reception mechanisms; however, NAPI has shortcomings and its performance can be further enhanced. A hybrid packet reception scheme that switches between interrupt disabling-enabling (DE) and polling (NAPI) can better improve the performance of Gigabit network hosts. In this paper we prove experimentally that the hybrid scheme can boost under different traffic load conditions the performance of general-purpose network desktops or servers running network I/O-bound applications. The implementation of the hybrid scheme is done in the latest version of Linux kernel 2.6.15.