Debugging Scalable Applications on the XT

Debugging at large scale on the Cray XT can involve a combination of interactive and non-interactive debugging; the paper will review subset attach and provide some recommendations for interactive debugging at large scale, and will introduce the TVScript feature of TotalView which provides for noninteractive debugging. Because many users of Cray XT systems are not physically co-located with the HPC centers on which they develop and run their applications, the paper will also cover the new TotalView Remote Display Client, which allows remote scientists and computer scientists to easily create a connection over which they can use TotalView interactively. The paper will conclude with a brief update on two topics presented at the previous two CUG meetings: memory debugging on the Cray XT and Record and Replay Debugging.