TR-10-01 RCRTool: Design Document; Version 0.1

Allan Porterfield, Rob Fowler, Min Yeol Lim. RCRTool: Design Document; Version 0.1, Technical Report TR-10-01, RENCI, North Carolina, February 2010.

RCRTool, Resource Centric Reflection Tool, will allow application programmers to better understand resource contention between multiple threads of a single application or between simultaneously active applications sharing varying levels of hardware. The improved knowledge of how the entire system is performing will be available to applications and runtimes for dynamic performance tuning. This document provides some of the motivation and the initial design of the entire system including access of hardware and OS performance counters, system modeling with that data, API that allow access to the data by runtimes and applications, and a data logging facility for post-run analysis.

The design attempts to allow the same tool to be used with a future single shared address node (with tens of cores) and with a distributed memory system with tens of thousands of nodes and hundreds of thousands of cores. The di erence between these systems, should be contained by di erence in what parts of the system are watched for potential bottlenecks and the granularity of available dynamic feedback.

At the center of RCRTool will be the RCRdaemon. It will have several jobs, including watching the hardware and OS for performance bottlenecks using performance models. RCRTool will supply some models, but mechanisms for the user to add their own will exist. RCRdaemon will also be responsible for transmitting the current state of the system to applications and the OS for dynamic tuning. A third function of the daemon will be logging the information for post-execution analysis.