Optimizing a CORBA Internet inter-ORB protocol (IIOP) engine for minimal footprint embedded multimedia systems

To support the quality-of-service (QoS) requirements of embedded multimedia applications off-the-shelf middleware like common object request broker architecture (CORBA) must be flexible, efficient, and predictable. Moreover, stringent memory constraints imposed by embedded system hardware necessitates a minimal footprint for middleware that supports multimedia applications. This paper provides three contributions toward developing efficient object request broker´s (ORBs) middleware to support embedded multimedia applications. First, we describe optimization principle patterns used to develop a time and space-efficient CORBA inter-ORB protocol (IIOP) interpreter for the adaptive communication environment (ACE)-ORB (TAO), which is our high-performance, real-time ORB. Second, we describe the optimizations applied to TAO´s interface definition language (IDL) compiler to generate efficient and small stubs/skeletons used in TAO´s IIOP protocol engine. Third, we empirically compare the performance and memory footprint of interpretive (de)marshaling versus compiled (de)marshaling for a wide range of IDL data types. Applying our optimization principle patterns to TAO´s IIOP protocol engine improved its interpretive (de)marshaling performance to the point where it is now comparable to the performance of compiled (de)marshaling. Moreover, our IDL compiler optimizations generate interpreted stubs/skeletons whose footprint is substantially smaller than compiled stubs/skeletons. Our results illustrate that careful application of optimization principle patterns can yield both time and space-efficient standards-based middleware