Examining Resource Use

Panning Across Resource Data

The Overview pane shows resource metrics for the duration of vanderbilt's execution.

By default, the metrics shown are the percentage distribution of CPU time in user space and in system space. The line colors in the graph correspond to the colors of the selected buttons in the Resources Shown box below.

Click on one or two other resource buttons to add those metrics to the graph.

Then, use the mouse to move the vertical yellow bar within the graph. Notice that the Sample box below reports the number of the data sample that the yellow bar is presently indicating. At the same time the Stack Trace box reports the stack trace at that sample point.

You can pan across resource data in this way to help identify the parts of the program where resource use seems excessive.

Zooming In on the Data

Place the cursor on the yellow vertical bar in the Overview graph and press the left mouse button. Then, holding the mouse button down, drag the bar a short distance across the graph. Notice what happens to the Exploded View graph when you release the mouse button (Title not available).

Figure 2-7 An Exploded View in the Pan/Zoom Resource Use Window

The data shown in the Exploded View graph corresponds to the highlighted part of the Overview graph where you dragged the bar. The subset of samples shown is indicated by the sample numbers shown below the Exploded View graph. The yellow vertical bar indicates the same point in program execution in both graphs.

Check the list under Total for Exploded View (to the right of the Resource... buttons) to see the numeric values of the selected metrics in the data subset.

Continue zooming in on the same or other parts of vanderbilt. Use the mouse to drag the yellow vertical bar across a portion of either graph, and the selected subset appears as the exploded view when you release the mouse button. Copy that view to a new window by clicking on the Copy Graph button; then select and copy another exploded view to compare with the first.

You can zoom in on data in this way to get a better look at the performance metrics for compute-bound parts of your program.

Note on Threaded Programs

If your example program is CMA threaded, you can use the Thread box to indicate which thread's stack trace should be shown in the Stack Trace box. The status of the chosen thread (Running, Ready, Blocked, or Nonexistent) is shown in the Thread Status box.

Notice that choosing a thread affects only the Stack Trace part of the analysis. The metrics shown in the Overview and Exploded View panes are per-process, not per-thread.

Viewing Source Code

Now, click the left mouse button on any spot in either graph pane on the Pan/Zoom window. The Source Display window appears (Title not available), showing the source code that corresponds to the leaf routine at the sample point indicated by the yellow vertical bar.

Figure 2-8 The Source Display Window

This exercise assumes that you copied vanderbilt.c to your present working directory. If source code does not appear in the Source Display window, click on the File:... menu on that window to bring up a dialog box where you can enter a search path for the source code.

Closing the Pan/Zoom Window

Click on File:Close to close the Pan/Zoom window and return to the main Puma window.