User Guide

Contents

Top-down Tree Comparison

To understand how your application call tree has changed after your optimization and see the difference in performance metrics per function and its callees, click the
Top-down Tree
sub-tab and explore the
Top-down Tree
window.
In the compare mode, the
Top-down Tree
window shows the data columns of the two results and a new column showing the difference between the two results for each program unit. The difference is calculated as <Result 1 Value> - <Result 2 Value>.
The
Top-down Tree
window in the compare mode supports two types of grouping levels:
  • Function Stack
    granularity groups the data by function instances. Use the
    Start Address
    column to identify different instances of the same source function or same loop.
  • Source Function Stack
    granularity groups the data by source functions. In this mode, all instances of the same source function are aggregated into one function.
Example: Comparison for Hotspots Analysis Results
The function
foo()
is called from two places in your application,
bar1()
and
bar2()
. If you see that foo() became slower in result 2, use the
Top-down Tree
window (compare mode) to check whether it became slower when being called by
bar1()
, by
bar2()
, or both.
To compare results with stacks and without stacks, switch the Call Stack Mode filterbar option to
User/System functions
to attribute performance data to functions where samples occurred.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.