Upshot shows a horizontal time line for each process, with colored bars to represent different states. It is possible to scroll smoothly through time with scrollbars at the top of the display.
One can also mouse-click on specific events to pop up data boxes that show the rest of the data logged in the event. We have found this type of display particularly valuable when the parallel program contained work units of widely varying grain size and changed it behavior during the run. Our parallel automated reasoning program Roo[8] is an excellent example of this type of program. Upshot has been used to trace programs written Strand[4], PCN[2], Prolog, and Fortran, as well as C.