Question 2022.3.7f1 HDRP experiences severe performance degradation every few seconds

Please fix it as soon as possible ...

 

This is a profiler thing. If you do not have the profiler open it does/should not happen.
Seems to be related to the memory profiler, so maybe close that?

 

There is also a noticeable delay with an empty scene and no other tools open.

 

Then profile that with just the CPU profiler maybe

 

To clarify @DevDunk's point: the 0.40ms for collecting memory stats as shown in the Timeline view here would go away if you were to remove the Memory Profiler Module from the Profiler Window using the top left hand drop-down in the window.

BUT: we can't tell you if that would make the spike go away because the Timeline view here shows the data for the latest (right-most) frame and not for the frame with the spike of 16ms.

Also, chances are that this is related to the Editor so even if you clicked on it, Timeline might just show you a nearly 15 Ms long strip for the "EditorLoop". If that's the case then switch the Profiler target from "Playmode" to "Editor" and profile that again to get details of what causes the spike. If that's not enough detail, then turn on Deep Profiling.

 

I found the problem, but I don't know what's causing

 

Have you unfolded that GameView.Repaint? Have you unfolded it until the big chunk of time dilutes into smaller chunks?

 

Is that the problem?

 

Probably somewhere in there, but it looks like you've disabled Deep Profiling again so there are no further details on what is probably some managed (read C#) code that is executed in that scope.

If Deep Profiling doesn't add any data, it might also be worth looking at this in Timeline view instead of Hierarchy and see if any other thread does something simultaneous to that long wait, like GC.Collect, which would stop-the-world, i.e pause all other threads, while it processes.