Ten Microseconds Over LAN, for Free (Extended)

The status quo for time stamping in personal computers (PCs) is ntpd, which, under general conditions, is accurate to 1 ms at best. For precision applications, it is inadequate, but it is a low-cost solution that suits many generic applications. IEEE-1588 provides mechanisms for submicrosecond accuracy, but to achieve this, more hardware is needed. We have developed the TSCclock, which gives the performance between these two solutions [about 10 mus on a local area network (LAN)] beyond submilliseconds using commodity hardware. We benchmark the TSCclock to show its potential as an inexpensive yet accurate software clock, which can be used with IEEE-1588 for LANs but has wider applicability as a replacement to ntpd.