Timestamps in Message-Passing Systems That Preserve the Partial Ordering

Timestamping is a common method of totally ordering events in concurrent programs. However, for applications requiring access to the global state, a total ordering is inappro­ priate. This paper presents algorithms for timestamping events in both synchronous and asynchronous n1essage-passing programs that allow for access to the partial ordering in­ herent in a parallel system. The algorithms do not change the con1munications graph or require a central timestamp issuing authority.