Approximate Algorithms for Optimization of Busy Waiting in Parallel Programs

Traditional implementations of conditional critical regions and monitors can lead to unproductive "busy waiting" if processes are allowed to wait on arbitrary boolean expressions. Techniques from global flow analysis may be employed at compile time to obtain information about which critical regions (monitor calls) are enabled by the execution of a given critical region (monitor call). We investigate the complexity of computing this information and show how it can be used to obtain efficient scheduling algorithms with less busy waiting.