The Timeline tab shows a chart of the events and the sample points recorded by the Collector as a function of time. Data is displayed in horizontal bars. For each experiment there is a bar for sample data and a set of bars for each LWP. The set for an LWP consists of one bar for each data type recorded: clock-based profiling, hardware counter overflow profiling, synchronization tracing, heap tracing, and MPI tracing.
The bars that contain sample data show a color-coded representation of the time spent in each microstate for each sample. Samples are displayed as a period of time because the data in a sample point represents time spent between that point and the previous point. Clicking a sample displays the data for that sample in the Event tab.
The profiling data or tracing data bars show an event marker for each event recorded. The event markers consist of a color-coded representation of the call stack recorded with the event, as a stack of colored rectangles. Clicking a colored rectangle in an event marker selects the corresponding function and PC and displays the data for that event and that function in the Event tab. The selection is highlighted in both the Event tab and the Legend tab, and selecting the Source tab or Disassembly tab positions the tab display at the line corresponding to that frame in the call stack.
For some kinds of data, events may overlap and not be visible. Whenever two or more events would appear at exactly the same position, only one is drawn; if there are two or more events within one or two pixels, all are drawn. although they may not be visually distinguishable. In either case, a small gray tick mark is displayed below the drawn events indicating the overlap.
The Timeline tab of the Set Data Presentation dialog box allows you to change the types of event-specific data that are shown; to select the display of event-specific data for threads, LWPs, or CPUs; to choose to align the call stack representation at the root or at the leaf; and to choose the number of levels of the call stack that are displayed.
You can change the types of event-specific data shown in the Timeline tab, as well as the colors mapped to selected functions. For details about using the Timeline tab, refer to the online help.