Logfile Creation and Teeshot

The second profiling library generates logfiles, which are files of timestamped events. During execution, calls to MPI_Log_event are made to store events of certain types in memory, and these memory buffers are collected and merged in parallel during MPI_Finalize. During execution, MPI_Pcontrol can be used to suspend and restart logging operations. The logfile produced at the end can be analyzed by a variety of tools. One that we use is called Teeshot, which is a derivative of Upshot [3], written in Tcl/Tk. A screen dump of Teeshot in use is shown in Figure 2.

  

Figure: A screendump from Teeshot

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It shows parallel time lines with process states, like one of the paraGraph [2]. The view can be zoomed in or out, horizontally or vertically, centered on any point in the display chosen with the mouse. In Figure 2, the middle window has resulted from zooming in on the upper window at a chosen point to show more detail. The window at the bottom of the screen show a histogram of state durations, with several adjustable parameters.