The effect of object-agent interactions on the performance of CORBA systems

The notion of middleware has been introduced to provide interoperability as well as transparent location of servers in heterogeneous client server environments. Although such benefits accrue from the use of middleware, careful consideration of system architecture is required to achieve high performance. Based on implementation and measurements made on the system, the paper is concerned with the impact of client agent server interaction architecture on the performance of a CORBA System. CORBA or Common Object Request Broker Architecture proposed by the Object Management Group is one of the commonly used standards for middleware architecture. Using a commercially available CORBA compliant ORB software called ORBeline, we have implemented two different architectures for client agent server interaction on a network of workstations. In the Handle Driven ORB architecture the client gets the address of the server from the agent and communicates with the server directly. In the Forwarding ORB architecture the client request is automatically forwarded by the agent to the appropriate server which then returns the results of the computations to the client. Our measurements show that the differences among the performance of these architectures change with a change in the workload. The paper reports on the relative performance of the two architectures under different workload conditions. The results provide insights into system behavior. In particular the impact of message size on the latency and scalability attributes of these architectures is analyzed. A discussion of how agent cloning can improve system performance is also included