One embodiment sets forth a technique for scheduling the execution of ordered critical code sections by multiple threads. A multithreaded processor includes an instruction scheduling unit that is configured to schedule threads to process ordered critical code sections. A ordered critical code section is preceded by a barrier instruction and when all of the threads have reached the barrier instruction, the instruction scheduling unit controls the thread execution order by selecting each thread for execution based on logical identifiers associated with the threads. The logical identifiers are mapped to physical identifiers that are referenced by the multithreaded processor during execution of the threads. The logical identifiers are used by the instruction scheduling unit to control the order in which the threads execute the ordered critical code section.