US Patent 7453910 Synchronization of independent clocks

A system and method to synchronize independent local clocks in multi-core processing system are disclosed. A shared counter or a shared memory/file is provided to establish a partial happened-before relationship (e1<e2 in the happened-before order if we know that the event e1 happened before the event e2) and a synchronizer device is utilized to generate a global time of events in threads or processes. The synchronizer device estimates each clock's start time and approximates elapsed time between events in threads or processes by executing an all-pair shortest-path algorithm.