C# Garbage Collector Begin/End Callback

Question

I was just wondering if there is an overridable callback for the garbage collector begin/end in the .NET runtime/C#. I will also state that I have no intentions of attempting to control the GC, I am just curious.

And if not, what would be the best way to replicate this behavior?

https://msdn.microsoft.com/en-us/library/cc713687.aspx and http://stackoverflow.com/questions/3678056/is-there-an-event-for-when-garbage-collection-occurs-in-net may be of some help. — Ron Beyer, May 24 '15 at 17:16

score 6 · Accepted Answer · edited May 23 '17 at 12:14

6

You can't get notification directly in manged code because managed code is suspended (or at least not guaranteed to run your thread in case of background GC) during GC.

Options:

You can get approximate notification with GC.RegisterForFullGCNotification as shown in Garbage Collection Notifications article.
You can watch performance counters related to GC if you need approximate time.
You can also capture ETW events to analyze behavior off-line - Garbage Collection ETW Events. There are many links on how to do that - Windows Performance Toolkit and SO questions like Consuming "Event Tracing for Windows" events.
If really necessary you can host CLR yourself and than you'll get notifications about GC - see CLR Indie Out:Hosting CLR and CLR Hosting - part 3. The ultimate method you want when hosting CLR to capture start/end of GC - IHostGCManager::SuspensionStarting.

edited May 23 '17 at 12:14

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answered May 24 '15 at 17:28

Alexei Levenkov

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Managed code cannot run during compactation regardless of the GC flavor. Besides this it is a really good answer. – Alois Kraus May 24 '15 at 17:43
@AloisKraus It is somewhat open question if OP wanted to measure whole begin/end or just precise suspension time... I've added link to the article that talks about difference, but one would need to read way more to know what to measure... – Alexei Levenkov May 24 '15 at 18:27
@AlexeiLevenkov I was planning on logging frequency after specific tasks. Game cycles and what have you. – Krythic May 24 '15 at 18:31
@Krythic perfcounters would likely be good enough - https://msdn.microsoft.com/en-us/library/system.diagnostics.performancecounter.aspx, http://blogs.msdn.com/b/maoni/archive/2004/06/03/148029.aspx – Alexei Levenkov May 24 '15 at 18:36

C# Garbage Collector Begin/End Callback

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