Stanford Seminar - Nanosecond-level Clock Synchronization in a Data Center

Mendel Rosenblum
Stanford University

April 24, 2019
Computers connected by networks have long used protocols like Network Time Protocol (NTP) to adjust the clocks of the computers to show the same time of day. With machines connected by a high performance network in a data center, NTP can keep the clocks within a few hundred microseconds of each other, a clock skew that is fine for humans but not useful for distributed system software that can communicate between machines in a few tens of microseconds. In this talk I will describe the challenge of tightly synchronizing clocks in a data center and present Huygens, a new algorithm developed with my colleague Balaji Prabhakar's research group that can synchronized data center clocks within few 10s of nanoseconds. Like NTP, Huygens requires no special hardware and simply exchanges messages between machines but uses a number of techniques that exploit the high-performance networks in data centers. The techniques include sending many more probe messages and then using sophisticated machine learning techniques and global knowledge to compute the clock adjustment operations to keep the clock synchronized.

View the full playlist:    • Stanford EE380-Colloquium on Computer Syst...