When you see the memory usage increase in your applications, it can be a challenge to find the root cause. In that case capturing and analyzing memory dumps may be your last best option. In this post I'll show you how you can use Visual Studio to analyze your memory dumps.
Create a dump file
Before we can analyze a memory dump, we first need to create a dump file.
One way to do this is through the dotnet monitor command line tool or you can do it directly from the Task Manager by right-clicking on the desired process and choosing Create dump file:
Analyze the dump file in Visual Studio
Now that we have a dump file, we can open it in Visual Studio.
- Open the dmp file in Visual Studio
- Choose Debug Managed Memory from the list of actions. Visual Studio will try to load all the symbols and analyze all the memory information in the dump file. Be patient as this can take a while.
- Once Visual Studio has done its work, you will see the Managed Memory viewer. This shows you all the object types found in memory, their number of occurrences, the size of these objects and their inclusive size.
That is already a good starting point to find out possible candidates that could cause a memory leak.
Compare 2 dump files
To help you in your investigation, it is also possible to compare 2 memory dumps and to see the differences. This is something I use a lot as it shows me exactly what is causing the increase in memory usage.
- Click on the Compare with baseline dropdown and choose Browse…
- This will open a file dialog where you can select another dump file. After selecting a second file click on Open to let Visual Studio load and process the file.
- Once the processing has completed, the Managed Memory viewer shows some extra columns where you see the difference in number of occurences, size and inclusive size.
Happy debugging!
Remark: Also have a look at the following video: