Using Lock-Free Objects in Hard Real-Time Applications

asses both static and dynamic priority schemes. The scheduling conditions we derive show that for hard real-time applications on a uniprocessor, lock-free objects often incur less overhead than either wait-free objects or lock-based objects implemented using the PCP. From a real-time perspective, lock-free objects are of Work supported by NSF Contract CCR 9216421. 1 A task is a sequential program that is invoked in response to an external stimulus or timer, and that must complete execution by a specified deadline. Tasks are usually prioritized and multiprogrammed on a single processor. 2 Such systems must guarantee that no deadline is ever missed. interest because they do not give rise to priority inversions, and can be implemented with minimal operating system support. Despite these advantages, it may seem that unbounded retry loops render such objects useless in hard real-time systems. Nonetheless, we