Abstract: Techniques for performing efficient automatic test-pattern generation (ATPG) are disclosed. ATPG may be performed by ATPG workers whose fault states are synchronized by an ATPG manager. In some embodiments, test-pattern generation by a ATPG worker may be performed multiple times with minimal idle time between generation and fault simulation intervals. Synchronization schemes may be synchronous or asynchronous. In asynchronous schemes, an ATPG worker may determine staleness of its fault state. If the fault state is stale, the ATPG worker may poll the ATPG manager to update the fault state to the current fault state of the ATPG manager which includes information on faults detected (including duplicate faults) by other ATPG workers. In synchronous schemes, fault states may be synchronized without polling by the ATPG worker. The synchronization of fault states via communication between manager and workers may reduce duplication and idle time, hence improving the time efficiency of ATPG workers.