The data in the call chains report is categorized hierarchically, meaning that, to see a function's subordinate functions, you have to expand it by clicking on the disclosure controls to the left of the function name, or pressing the right arrow key on your keyboard. To hide a link's subordinate functions, click the disclosure button again or press the left arrow key. This functionality is shown in Figure 6.7.

Figure 6.7. The hierarchical call chains display

If you take a look at the call chain shown in Figure 6.7, you can see that the link decoder_resize has been expanded to show three of its child functions. Exploring the links in the call chains report in this manner is a good way to pinpoint exactly where the time is spent in your code.

The call chains report's toolbar contains all of the standard table report buttons and six other buttons, not found in the other report types. The button, located just to the right of the standard toolbar options, hides all the children of all links, while the button to its right, expands it to show every subordinate branch of all links. The filtering buttons are located to the right of these disclosure control buttons. For more information on their functionality, see Call chains report filtering. To the right of the filtering buttons are the call chain link note buttons. For more information on using the next and previous call chain link buttons, see Call chains link notes.

The call chains report also contains two unique contextual menu item, Expand Selection To All Matching Call Chain Links and Collapse Unselected Call Chain Links. Use the Expand Selection To All Matching Call Chain Links option, only present if the function appears in the call chains report more than once, to select all of this function's call chain links. The hierarchical table expands to show each of the newly selected links. The Collapse Unselected Call Chain Links option collapses every unselected call link subordinate to the selected function.