Using Key Object Opportunism to Collect Old Objects

Abstract

Object allocationand deallocation data gathered for the Cedar system on Xerox Dorados supports the weak generational hypothesis!newly-created objects have a much lower survival rate than objects that are older.The survivors at all collections thresholds are highly organized; large clusters of objects are allocated at roughly the same time, and live for roughly the same length of time.By cleverly selecting representatives from the clusters and examining the reachability of these key objects more frequently than the cluster itself, the storage system can use the death of these key objects to find good opportunities to collect the clusters they represent.