Guidelines for data-parallel cycle-stealing in networks of workstations

We derive guidelines for nearly optimally scheduling data-parallel computations within a draconian mode of cycle-stealing in NOWs. In this computing regimen, workstation A takes control of workstation B´s processor whenever B is idle, with the promise of relinquishing control immediately upon demand, thereby losing work in progress. The typically high communication overhead for supplying workstation B with work and receiving its results militates in favor of supplying B with large amounts of work at a time; the risk of losing work in progress when B is reclaimed militates in favor of supplying B with a succession of small bundles of work. The challenge is to balance these two pressures in a way that maximizes (some measure of) the amount of work accomplished. Our guidelines attempt to maximize the expected work accomplished by workstation B in an episode of cycle-stealing, assuming knowledge of the instantaneous probability of workstation B´s being reclaimed. Our study is a step toward rendering prescriptive the descriptive study of cycle-stealing in (Bhatt et al., 1997)