Adaptive Locks for Frequently Scheduled Tasks With Unpredictable Runtimes

We present a form of discretionary lock which is designed to render unreliable but frequently scheduled scripts or programs predictable even when the execution time of locked operations may grow and exceed their expected scheduling interval. We implement our locking policy with lock-unlock semantics and test them on the system administration language cfengine. The locks are controlled by too-soon and too-late parameters so that execution times can be controlled within fixed bounds even when scheduling requests occur randomly in addition to the periodic scheduling time. This has the added bonus of providing an anti-spamming functionality.