USENIX Technical Program - Abstract - COOTS 99
Applying Optimization Principle Patterns to Design Real-Time ORBs
Irfan Pyarali, Carlos O'Ryan, Douglas Schmidt, Nanbor Wang, and Vishal Kachroo, Washington University, St. Louis; Aniruddha Gokhale, Lucent Technologies, Bell Labs
First-generation CORBA middleware was reasonably successful at
meeting the demands of request/response applications with best-effort
quality of service (QoS) requirements. Supporting applications with
more stringent QoS requirements poses new challenges for
next-generation real-time CORBA middleware, however. This paper
provides three contributions to the design and optimization of
real-time CORBA middleware. First, we outline the challenges faced by
real-time ORBs implementers, focusing on optimization principle
patterns that can be applied to CORBA's Object Adapter and ORB Core.
Second, we describe how TAO, our real-time CORBA implementation,
addresses these challenges and applies key ORB optimization principle
patterns. Third, we present the results of empirical benchmarks that
compare the impact of TAO's design strategies on ORB efficiency,
predictability, and scalability.
Our findings indicate that ORBs must be highly configurable and
adaptable to meet the QoS requirements for a wide range of real-time
applications. In addition, we show how TAO can be configured to
perform predictably and scalably, which is essential to support
real-time applications. A key result of our work is to demonstrate
that the ability of CORBA ORBs to support real-time systems is mostly
an implementation detail. Thus, relatively few changes are required
to the standard CORBA reference model and programming API to support
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