The design and performance of a real-time CORBA scheduling service

There is increasing demand to extend CORBA middleware to support applications with stringent quality of service (QoS) requirements. However, conventional CORBA middleware does not define standard features to dynamically schedule operations for applications that possess deterministic real-time requirements. This paper presents three contributions to the study of real-time CORBA operation scheduling strategies. First, we document our evolution from static to dynamic scheduling for applications with deterministic real-time requirements. Second, we describe the flexible scheduling service framework in our real-time CORBA implementation, TAO, which supports core scheduling strategies efficiently. Third, we present results from empirical benchmarks that quantify the behavior of these scheduling strategies and assess the overhead of dynamic scheduling in TAO. Our empirical results using TAO show that dynamic scheduling of CORBA operations can be deterministic and can achieve acceptable latency for operations, even with moderate levels of queueing.