Odd application performance degradation

Question

We have an application mixed with .NET 2.0 and native C ++. In our testing, we have a mode that can automatically go through a set of projects. The project opens, starts, closes, repeats. Each of these steps requires the creation / destruction of windows (more precisely, winforms). We recently encountered some odd performance behavior. After several hours of operation, the opening and closing of parts slows down (blocking the gui flow and displaying half drawings, etc.). Now it would be easy to crack it before the resource leaks ... but we are tracking descriptors and memory, and while memory is growing a bit, nothing indicates this level of problem. Handles are stable. So maybe tattered event handlers ... you still need to investigate this. But the kicker that puzzles me isthat closing the application and restarting it does not return the original performance. It is still slow until I restart the OS (win XP) and then start working again again. This really puzzles me, as I assume that closing the application will return all resources. Any thoughts?

Answer 1

We skipped window classes

Answer 2

Sounds like a possible GDI descriptor leak. GDI objects are not automatically picked up by the garbage collector.

The .NET Memory Profiler ( http://memprofiler.com/ ) tracks them well (there is a 14-day trial version).

You saw them:

• Resource Leaks: Detecting, Localizing, and Fixing GDI Hidden Code

• Detection and connection of GDI leaks in your code using two powerful tools for Windows XP (there is a link to the GDI Handle viewer tool).

Answer 3

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