There are 4 graphical visualization tools distributed with MPE, they are upshot, nupshot, Jumpshot-2 and Jumpshot-3. Out of these 4 Logfile Viewers, only 3 viewers are built by MPE. They are upshot, Jumpshot-2 and Jumpshot-3.
One tool that we use is called upshot, which is a derivative of Upshot [3], written in Tcl/Tk. A screen dump of Upshot in use is shown in Figure 1 .
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 1 , 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.
Nupshot is a version of upshot that is faster but requires an older version of Tcl/Tk. Because of this limitation, Nupshot is NOT built by default in current MPE.
There are 2 versions of Jumpshot distributed with the MPE. They are Jumpshot-2 and Jumpshot-3, which have evolved from Upshot and Nupshot. Both are written in Java, are graphical visualization tools for interpreting binary tracefiles which displays them onto a canvas object, such as the one depicted in Figure 2 . For Jumpshot-2, See [5] for more screenshots and details. For Jumpshot-3, See file mpe/viewers/jumpshot-3/doc/TourStepByStep.pdf for a brief introduction of the tool.
As the size of the logfile increases, Jumpshot-2's performance decreases, and can ultimately result in Jumpshot-2 hanging while it is reading in the logfile. It is hard to determine at what point Jumpshot-2 will hang, but we have seen it with files as small as 10MB. When CLOG file is about 4MB in size, the performance of Jumpshot-2 starts to deterioate significantly. There is a current research effort that will result in the ability to make the Java based display program significantly more scalable. The results of the first iteration of this effort are SLOG which supports scalable logging of data and Jumpshot-3 which reads SLOG.