Walkthrough - Comparing Memory Profiling Runs

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The third step in profiling the memory usage of your .NET managed program is to compare the memory profiling data snapshots that you have collected. Memory profiling data diffs help you identify which methods or classes are responsible for allocating the largest amounts of memory during the interval between two snapshots.

To create a diff:

1.    Select a snapshot to compare. To select a snapshot, click the memory profiling Data Browser window for the snapshot, or double-click the snapshot entry images\navsnap.gif in the Navigator.

2.    Click images\diffic.gif

3.    Select a snapshot (identified as the Base run) to compare against an earlier snapshot (identified as the New run, and also labeled Current run in the Compare Runs dialog box).

4.    Click OK.

5.    Purify creates a diff entry images\navdiff.gif in the Navigator, and displays the memory profiling data for the diff in a new memory profiling Data Browser window.

Purify highlights changes in memory use in the diff Call Graph. Methods or paths where memory use has decreased appear in green; increases appear in red. Methods or paths where memory use is unchanged appear in gray.

The Function List View displays the differences, as well as the original data, for the two snapshots (labeled New and Base). Negative values indicate decreased memory use.

Notes:

§      Diffs do not display information about objects. Use a diff to identify problem paths and methods, then select the later of the two snapshots used to create the diff to see detailed information about method objects.

§      The Details tab of the Properties dialog box for the diff entry identifies the snapshots that were used to create the diff.

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