When does the CLR call the garbage collector in .net?

Question

Can someone tell me when the garbage collector will be called? Does it continue in the background thread? How does the garbage collector know that I need to clear the generation of the memory form?

Answer 1

If you want to know exaccty if GC compiles, you can use this class:

public class GCWatcher { protected override void Finalize() { Debug.Print("GC on the prowl"); try { if (!AppDomain.CurrentDomain.IsFinalizingForUnload() && !Environment.HasShutdownStarted) { GCWatcher g = new GCWatcher(); } } catch { // nothing to do, but in case of error, the GC should continue anyway! } } } 

A source

The class instantiates when it ends with GC. In addition, it prints a message when the GC starts up.

You can also take a look at the links provided in the comments to get a deep dive into the .NET GC here and here .

Answer 2

The garbage collector runs:

• When your code tries to allocate memory and there is not enough space on the heap.
• When systems send a signal to an application to try to use less resources (for example, while minimizing the application).
• Whenever the garbage collector feels that it would be useful, for example, maybe if there is little space left for the heap and your application is busy doing I / O operations anyway.

Exactly how the garbage collector determines when it should start is an implementation detail, so it may differ between versions of the framework.

The garbage collector does not start continuously. When it starts all other threads in the application, they are frozen, so the garbage collector has only control over the memory.

Answer 3

The garbage collector does not work continuously; it launches a single “collection” at a time (which may affect multiple GC generations).

When it is called (ignored by GC.Collect() ), it is not deterministic, and I believe that this is a detail of the CLR implementation, and not part of the specification.

However, the current .NET GC will start whenever a program tries to allocate memory in a managed heap, and there is not enough free memory to do this. The collection frees up space and defragments the contents of the heap, leaving space for distribution.

Everything that survives in the Gen0 collection extends to Gen1; if there is not enough space in Gen1 for promoted items, then Gen1 is also collected. The same thing happens between Gen1 and Gen2.

Answer 4

• When Gen 0 objects reach ~ 256KB.
• When Gen 1 objects reached ~ 2Mb.
• When Gen 2 objects reached ~ 10Mb.
• When system memory is low.