View Comparison Data
Intel® VTune™
compares analysis results and displays difference in a separate result tab
Profiler
<result1>-<result2>
in the following windows:
- Summarywindow provides top-level difference for the analysis run.
- Bottom-upwindow displays difference for functions and their callers per metric.
- Top-down Treewindow displays difference for functions and their callees per metric.
- Caller/Calleewindow displays difference for a selected function, their callers and callees per metric.
Comparing Recompiled Binary Files
By default, the
VTune
displays compared functions grouped by the
Profiler
Call Stack
granularity, which is based on function instances. But you may want to switch to the
Source Function Stack
grouping to get more accurate comparison results in the following cases:
- You slightly changed the source and recompiled the code.
- You changed compilation options and recompiled the code.
- You are comparing results compiled and collected for different Intel microarchitectures
For example, your binary with a
my_f
function was modified with adding a new function
my_f1
and new calls of this function. As a result,
my_f
address has changed. If you compare the results before and after the modification using the default
Call Stack
grouping, the
VTune
treats the same functions with different addresses as separate instances and does not compare them:
Profiler

When the data is aggregated by
Source Function Stack
, the
VTune
ignores start addresses and compares functions by source file objects:
Profiler

Bar Data Respresentation
If you chose the
Bar
format to display the performance data in the
Bottom-up
or
Top-down Tree
window, the
VTune
calculates the bar size as follows:
Profiler
Result Data Column
| Difference Column
|
---|---|
cell_data_value/absolute_max_value_in_result_column | cell_data_value/max(absolute_max_value_in__1st_result_column, absolute_max_value_in_corresponding_2nd_result_column) |
Example: Calculation of the Bar Size
The table below provides an example on how the
VTune
calculates the bar size in the compare mode based on the absolute max CPU time value and performance data per column:
Profiler
CPU Time:r001
| CPU Time:r002
| CPU Time:Difference
| |
---|---|---|---|
Absolute max value (calculated by the
VTune
internally but not exposed in the grid)
Profiler | 10s
| 20s
| 20s
|
Performance data
| 1s
| 3s
| 2s
|
Bar size
| 1s/max(10s,20s)
| 3s/max(10s,20s)
| 2s/max(10s,20s)
|