Jinsight How-To Guide

 Analyze calling patterns and repetitive sequences

Once you have identified a problem area, use the techniques in this section to study it in more detail.
 
See calling relationships among a group of methods  Start with a group of methods you are studying, and sort out who is calling (and contributing time) to whom.

Why is a method taking so long?  A method is taking more time than you think it should, and you want to understand its behavior to optimize it.  This section will help you analyze the detailed activity of execution sequences.

Why is a method being called?  A method or sequence of methods is taking up much of your program's time.  There may be a higher-level performance problem, where the method is called too often.  Use these techniques to see when and why the method is called.

Work with repetitive patterns  Techniques to help you work with repetitive sequences.

 

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See calling relationships among a group of methods

1. Bring up the Method Histogram
2. Bring the most expensive methods to the top of the view: select Cumulative Time, then select Recalibrate Colors, then Sort Class Colors Now
3. Right-click on methods which you are studying, starting with the most expensive method, and select Show Callees (Top 5)

• Continue exploring the calling relationships among the methods, selecting either Show Callees (Top 5) or Show Callers (Top 5) on various methods.

• Look at the number next to each line, or fly over each line and look at the status area, to see the number of times each method is called by another method.

Why is a method taking so long?

1. From the Method Histogram, select the most expensive method of a group of methods you are studying
2. Bring up the Execution Pattern View

• The relative lengths of the bars show you the relative time spent in each method, aggregated over all instances of the pattern.

• You can cycle through the alternative subpatterns by pressing the gray buttons in the view.

Tip: clear the object selection after you have brought up the Execution Pattern View to make it easier to work with.
 
• If you want to look at the detail of individual invocations, bring up the Invocation Browser after you have selected a method.

Why is a method being called?

See what methods are calling a method

1. Bring up the Method Histogram
2. Right-click on the method you are studying, and select Show Callers (Top 5) from the menu

• Look at the number next to each line (or fly over the line and look at the status area) to see the number of times the method is invoked by this caller

• You may want to continue to draw lines further back in the calling sequence

See all the places a method is called

1. Bring up the Execution View
2. Select the method in the Method Histogram, or select any invocation of the method in the Execution View (click on or below the method name, but not on the vertical bar)

• Notice all of the places in the Execution View which are highlighted in yellow (Tip: use the <Home> key to zoom all the way out).  This will give you a sense of the phase of execution in which the method is called, and how much of the total time it is taking up.  It also will show you if this method is called often, and if it's part of a repetitive pattern.

See the context of each individual method invocation

1. Select the method in the Method Histogram
2. Bring up the Invocation Browser

• Cycle through the invocations, and click on the symbol [..] in the upper left corner to see the caller.

Work with repetitive patterns

See repetitive sequences in summary form or individually

1. Bring up the Method Histogram and select the method (or select it from any other view)
2. Bring up the Invocation Browser or the Execution Pattern View

Tip: clear the object selection after you have brought up the Invocation Browser or the Execution Pattern View to make it easier to work with.
 
• In the Invocation Browser, use the Next button to cycle through each invocation.

• In the Execution Pattern View, use the gray buttons in the view to look at alternative subpatterns.

• To explore invocations of another method, select the method (in any view), and then press the Update button in the Invocation Browser or Execution Pattern View.

See repetitive sequences in context

1. Bring up the Execution View
2. Zoom out far enough to see entire dense areas of activity you want to explore
3. Right click on a long bar where you think the repetitive sequence starts, or on the lines immediately to the right of it
4. Select Detect Repetition from the menu (Tip: if a menu with this item doesn't appear, make sure the cursor is positioned over an object or a method invocation. You can use the status bar to help position the cursor)

• If there is a repetitive pattern at this level, the detailed calling sequence will be replaced by a gray box showing a summarized view of the pattern.

• Look at the number which appears in the gray box.  This tells you the number of repetitions in the pattern.

• There are repetitive patterns which this feature is not able to detect, because of certain kinds of variation in the pattern.

• This will show only a single level of repetition, which may hide more detailed repetitive patterns further down the call stack.  So you may want to explore further by removing repetition detection at a high level and looking for finer repetition.

• You can also select Detect All Repetition from the menu bar.  This will display the highest-level instances of repetition throughout the program.