Publication Source: The 4th Workshop on Feedback-Directed and Dynamic Optimization (FDDO-4), Austin, TX, USA
The OOCT system implements dynamic optimization within a software emulation of Fujitsu’s K series mainframe architecture. OOCT compiles the instructions of the traditional K series operating system called ASP. The combined requirements of running below the OS and operating in a mainframe product restrict the features of OOCT on the one hand while providing opportunities for unusual optimizations and implementation techniques on the other. We describe the system structure to show where tradeoffs were made, providing details on some of the unusual features. We highlight the adaptive features of OOCT for balancing and delaying CPU load. Finally, we describe a set of lessons taken away from our experience with mainframe emulation.