High Performance Adaptive Middleware for CORBA-Based Systems
E-Kai Shen, Shikharesh Majumdar, Istabrak Abdul-Fatah
To appear at Nineteenth Annual
ACM SIGACT-SIGOPS Symposium on PRINCIPLES OF DISTRIBUTED COMPUTING (PODC
2000), Portland, Oregon, 16-19 July 2000
Abstract
Middleware provides inter-operability and transparent location of servers
in a heterogeneous distributed environment. A careful design of the middleware
software is required however for achieving high performance. This research
proposes an adaptive middleware architecture for CORBA-based systems. The
adaptive middleware agent that maps an object name to the object reference
has two modes of operations. In the handle-driven mode it returns a reference
for the requested object to the client that uses this reference to re-send
the request for the desired operation to the server whereas in the forwarding
mode it forwards the entire client request to the server. The server upon
invocation performs the desired operation and returns the results to the
client. An adaptive ORB dynamically switches between these two modes depending
on the current system load. Using a commercial middleware prod uct called
Orbix-MT we have implemented a skeletal performance prototype for the adaptive
ORB. Based on measurements made on a network of workstations and a synthetic
workload we observe that the adaptive ORB can produce a substantial benefit
in performance in comparison to a pure handle-driven or a pure forwarding
ORB. Our measurements provide valuable insights into system behavior and
performance.