Before you begin analyzing your target for performance, you need to build it as follows:
Enable downloading debug information for the system libraries byconfiguring the Microsoft* Symbol Server to download automatically.
Enable debug information generation for your binary files by configuring your project settings.
Build your target in the Release mode.
Create a baseline against which you can compare the performance improvements as a result of tuning.
For example, you instrument your code to determine how long it takes to compress a certain file. Your original target code, augmented to provide these timing data, serves as your performance baseline. Every time you modify your target, compare the performance metrics of your optimized target with the baseline, to verify that the performance has improved.