AS-GC: An efficient generational garbage collector for Java']Java application servers

A generational collection strategy utilizing a single nursery cannot efficiently manage objects in application servers due to variance in their lifespans. In this paper, we introduce an optimization technique designed for application servers that exploits an observation that remotable objects are commonly used as gateways for client requests. Objects instantiated as part of these requests (remote objects) often live longer than objects not created to serve these remote requests (local objects). Thus, our scheme creates remote and local objects in two separate nurseries; each is properly sized to match the lifetime characteristic of the residing objects. We extended the generational collector in HotSpot to support the proposed optimization and found that given the same heap size, the proposed scheme can improve the maximum throughput of an application server by 14% over the default collector. It also allows the application server to handle 10% higher workload prior to memory exhaustion.