Distributed deadlock detection and resolution based on hardware clocks

Inexpensive but accurate hardware clocks are now commonplace on many systems. A clock synchronization protocol can keep the collection of clocks for a group of networked systems roughly synchronized without the expenditure of a great deal of processor time or network bandwidth. As long as the bounded skew between clocks is taken into account, rough real time can provide an intuitive and valuable mechanism for providing a notion of order in a distributed system. This paper presents a straightforward token-based protocol for the detection of distributed deadlock under the single resource model. It uses clock values as token time stamps to ensure that exactly one process in a deadlock cycle, the process that completed the cycle, detects the deadlock and aborts, breaking the deadlock. The clock-valued time stamps also ensure that no false deadlocks are detected, without additional protocol to eliminate obsolete tokens. Arguments for the correctness of the protocol are developed