A CPI breakdown model plug-in for optimizing application performance

Effectiveness and quality are fundamental characteristics for the development of a product. In order to support them, one needs to ensure that an application optimization level is at its best. The most widely used metric for evaluating an application performance is the CPI (Cycles Per Instruction), i.e., the number of clock cycles that takes place when an instruction is executed. We have developed a CPI Breakdown Model Plug-in, that automates the profiling of an application in the Power architecture, breaking it down into several groups of CPI events and metrics in order to identify possible bottlenecks. When analyzing such events and metrics the user can become aware of which operations are causing the processor to stall, and consequently enhance the application source code. We have discussed the adaptation of some command-line tools to be used by our CPI plug-in, which is integrated into the IBM Software Development Toolkit for PowerLinux, an Eclipse based IDE comprising a set of mainstream C/C++ development tools along with several in-house IBM ones. A case study that shows the usefulness of our approach is presented and details on how to optimize an application are discussed.