Jinsight Reference Manual

Visualizing a Program Trace

Scrolling · Zooming · Scaling one dimension · Selection · Navigation (drill down) · Flyover · Time measurements · Help.

Object Histogram View

This section describes features common to some or all of the views. Note that some of the behavior is different between the graphical views (Histogram, Execution, Execution Pattern, and Reference Pattern) and the text-based views (Table and Call Tree).

• Scrolling. The view may be larger than the window in which it appears.  When it is, scrollbars let you adjust what is visible in the view. 

  Histogram, Execution, Execution Pattern, and Reference Pattern views: In these views there are two additional ways to scroll:

• The arrow keys on the keyboard and/or numeric pad let you scroll the view incrementally in four directions.


• Ctrl-left-click anywhere in the view and hold down the mouse button.  This lets you scroll the view in two dimensions at once. We call this drag scrolling.

• Zooming.

  Histogram, Execution, Execution Pattern, and Reference Pattern views: These views lets you zoom in and out to vary the scale of what you see. Zooming in enlarges the view; zooming out reduces it.

• You can zoom in in any of three ways:
  • Press the "+" button near the bottom of the view.
  • Press the "+" key on the keyboard or numeric pad.
  • Drag the mouse (holding down the button) to display a rectangular area of varying size.  When you release the button, the view will zoom to display just that rectangular area.
• There are two ways to zoom out:
  
  • Press the "-" button near the bottom of the view. 
  • Press the "-" key on the keyboard or numeric pad
• Choosing Font Scaling from the view's Options menu will make text grow and shrink just like other elements of the view when it's zoomed.  Text remains a constant size by default, which may be preferable at extreme magnifications. 
• Use the "Home" key or menu command to return to the initial scale and scroll position—that is, the zoom factor, horizontal/vertical scaling, and scroll position they had when they first appeared on the screen.
• Some of these views also have a Zoom menu. You can set a bookmark with Mark Zoom and return to it with Zoom to Mark. A history is maintained, enabling Zoom Back, Zoom Forward, and Toggle Zoom functions.

 

• Scaling one dimension. In addition to zooming, some of the views let you scale either the horizontal or vertical dimension independently.

  Execution and Execution Pattern views: These views, which map time to a spatial dimension, let you compress and expand the time scale. 

  • You can compress the time scale in three ways:
    • Choose Compress Time from the Zoom menu.
      
    • Press the "<" (less than) key on the keyboard.
    • Press the "/" key on the numeric pad.
  • There are three ways to expand the time scale:
    
    • Choose Expand Time from the Zoom menu.
    • Press the ">" (greater than) key on the keyboard.
    • Press the "*" key on the numeric pad.

 

Histogram view: The Histogram view lets you compress and expand the horizontal dimension to make the histogram more or less compact.  You may use the "<", ">", "/", and "*" keys as above, or choose Compress and Expand from the Options menu.


Table view: The Table view lets you compress the vertical dimension, so you can see more rows in one view. This is typically used when displaying the data as bars. You may use the "<", ">", "/", and "*" keys as above, or choose Compress Rows and Expand Rows from the Rows menu. You may also use the arrows in the upper right corner of the view.

• Flyover.

  Histogram, Execution, Execution Pattern, and Reference Pattern views: These views include a status line at the bottom of the window.  The status line displays information about the item directly underneath the mouse pointer, if any.  For example, passing the mouse pointer over an object in the Histogram view will display information such as the object's class and instance identifier, its time of creation, cumulative time spent in its methods, and so forth.

  Table and Call Tree views: as you fly over the view with the mouse, a tooltip window will show you more detailed information about a particular cell or column heading.
   

• Selection.

  Every view lets you select one or more elements for subsequent analysis. Selected elements are highlighted in the current view and in all other views. Every view highlights selected elements using a yellow background. Other details of how selection is displayed vary from view to view.

The way you select items is similar in each view, though there are some differences.
• to make a selection, left-click the mouse over the item of interest.
• to add or remove an element from the selection, Ctrl-left-click with the mouse over that element.
• some of the views have additional selection functions available in the popup menu obtained by right-clicking the mouse
• in the Table and Call Tree views you may left-click and drag the mouse to select a number of rows at one time.

Once a selection has been made, functions are available in every view that let you use the selection to navigate to other views (see Navigation), or to filter and group information (see Slices and Workspaces: Introduction). Every view has a menu named Selected with these functions. These functions also appear in the popup menu you get by right-clicking in each view.

Note that right-clicking over a view works somewhat differently from view to view. In the Table and Call Tree views, right-clicking over a row will select that row if it's not already selected, and bring up a popup menu. In the other views, right-clicking only brings up the popup menu, and does not alter the current selection.

Note also that while Jinsight allows multiple elements to be selected, they must all be of the same type (classes or methods or threads, etc.).

• Navigation.

  You may select a number of elements from one view and then "drill down" to see them, or to see more detailed information about them, in another view. From the Selected menu in any view, or from the popup menu obtained by right-clicking, choose Drill Down to Selected Items. This will bring up a list of views which make sense for the type of elements that are currently selected.

  For example, if we have selected a method, we may navigate to an Execution Pattern, Table or Call Tree view (below) over all the invocations of the method.

Drilling down from a selected method to a Call Tree view of the invocations of that method

The system will automatically convert from one type of information to another as you drill down to more detailed views. Here are the conversions provided:

A selection of this type ...	May be automatically recast to open a view on ...
Package	All classes, all objects or all methods in the selected packages.
Class	All methods or all objects of the selected classes
Method	All invocations of the selected methods
Object	All invocations where the target object is currently selected
Thread	All invocations in the thread
Slice	All threads, packages, classes, methods, objects, or invocations in the user-defined Slice

Every view also has a function to set its contents based on whatever is currently selected. The details of this differ in each view. For example, in the Execution view, there is a menu item to display the currently selected threads only. Some of the views in addition have the ability to automatically update what is shown as the selection changes. This allows you to select items in one view while viewing detailed information about the selected items in another.

• Time measurements.

  The time units recorded in the trace depend upon the platform where your application was run:

• On Window systems, time units are recorded in thousands of Pentium CPU ticks (or "Kticks").  For example, one Ktick on a 200 MHz Pentium is approximately (1,000 ticks) / (200 MHz), or 5 microseconds. 
• On AIX and OS/390, time units are recorded in microseconds.

 

Two summary measures of time are shown in various views:

• Base time of a method invocation is the time spent executing this method only.  It does not include time spent in other Java methods this method calls, or time spent while other Java threads are executing.  It does, however, include time spent waiting for the completion of native methods and system functions called by this method.  It also includes time when this process is not active.  Note also that thread switches introduce uncertainty into this calculation, since the trace does not record them explicitly.  When a thread switch is detected, all the time expended in the most recent method is credited to the thread which was active before the switch. Important note: base time numbers are only meaningful if you have traced your application on a single processor machine.
• Cumulative time of a method invocation is the time the method spent on the execution stack, including both time spent in the method itself and in other methods that it calls.  It includes all time spent on the stack, including time spent in other Java threads, and time when this process is not active.  Note on summaries of cumulative time:  in the Histogram, Table, and Call Tree views, Jinsight presents summaries of cumulative time, formed by aggregating the cumulative time over a set of method invocations. Jinsight takes into account the fact that a given summary measure may represent time in calls that call each other; care is taken not to count time in any call more than once.

• Help. Every view provides a menu with help information. When the Help menu item is selected in a view, the Jinsight visualizer uses your browser to display the relevant page from the Jinsight Reference Manual. The visualizer uses environment variables JINSIGHT_BROWSER and JINSIGHT_DOC, provided in the installation batch file jinsight.bat, to find your browser and display the help information.

Visualizing a Program Trace

Jinsight Home

Histogram View