Improved algorithms for synchronizing computer network clocks
IEEE/ACM Transactions on Networking (TON)
Experience with an adaptive globally-synchronizing clock algorithm
Proceedings of the eleventh annual ACM symposium on Parallel algorithms and architectures
PC based precision timing without GPS
SIGMETRICS '02 Proceedings of the 2002 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
Fine-grained network time synchronization using reference broadcasts
ACM SIGOPS Operating Systems Review - OSDI '02: Proceedings of the 5th symposium on Operating systems design and implementation
Understanding the Linux Kernel, Second Edition
Understanding the Linux Kernel, Second Edition
Dynamic instrumentation of production systems
ATEC '04 Proceedings of the annual conference on USENIX Annual Technical Conference
Measuring and characterizing system behavior using kernel-level event logging
ATEC '00 Proceedings of the annual conference on USENIX Annual Technical Conference
Time synchronization in sensor networks: a survey
IEEE Network: The Magazine of Global Internetworking
A theoretical evaluation of peer-to-peer internal clock synchronization
Autonomics '08 Proceedings of the 2nd International Conference on Autonomic Computing and Communication Systems
| Hi-index | 0.00 |
Most computers have several high-resolution timing sources, from the programmable interrupt timer to the cycle counter. Yet, even at a precision of one cycle in ten millions, clocks may drift significantly in a single second at a clock frequency of several GHz. When tracing the low-level system events in computer clusters, such as packet sending or reception, each computer system records its own events using an internal clock. In order to properly understand the global system behavior and performance, as reported by the events recorded on each computer, it is important to estimate precisely the clock differences and drift between the different computers in the system. This article studies the clock precision and stability of several computer systems, with different architectures. It also studies the typical network delay characteristics, since time synchronization algorithms rely on the exchange of network packets and are dependent on the symmetry of the delays. A very precise clock, based on the atomic time provided by the GPS satellite network, was used as a reference to measure clock drifts and network delays. The results obtained are of immediate use to all applications which depend on computer clocks or network time synchronization accuracy.