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Regular hiccups - how to hunt down the cause?

I have a regular performance hiccups that occurs every ~20/40/60… seconds. Seems quite random. Game is running at stable 60 FPS, but it freezes for around ~0.2-0.5 second during one “hiccup” - but without affecting the actual FPS. It stays at 60 FPS during freeze.

How to hunt down things like this? How can I spot the problem causer? I know I can use profiler for finding bottlenecks during certain period of time, but how about 0.2-0.5s. random hiccup? I’m afraid I’m not that quick :slight_smile:
It occurs in every play mode: Separated window, Standalone and packaged game.

Generally, I have no idea how should I approach this problem. The only thing I can think of is to gradually delete blueprints and check when the hiccups would disappear, but it would be rather painful thing to do… + Maybe it’s even not related to blueprint logic… Any clues my friends?

Check out this link.
https://www.unrealengine.com/blog/how-to-improve-game-thread-cpu-performance

Also maybe you can bind the debug profiler through blueprints and have it print the results on a separate txt file. Use event tick and it will catch every frame.

I’ll try something like that, thanks for the hints!

It turned out that this is a garbage collection performing every 60s and freezing my game for 0.2/0.5s.
I don’t have many actors spawned/deleted (+ I’ve tested it by standing still and not doing ANYTHING), so I don’t know why it’s so slow? Is there any way to eliminate this problem?

Update: I’ve created an empty level and there it doesn’t freeze. I guess I’ll add more and more blueprints and see which one will cause these freezes by garbage collection…

Update2: Spotted! The freezes are caused by a post process library that I’ve bought (https://forums.unrealengine.com/showthread.php?76298-Chameleon-Post-Process-Material-Library). I’ll contact the author and post there with repro steps.

I had error logs from a failing connection to the network. I could see those logs in the session frontend of UE4. I think they originate from virtualbox virtual network controller… I deactivated and reactivated some of the network controllers in windows, and voila! No logs in the session frontend of UE4, neither hiccups! Cool, but so strange!!!

Thanks ! I have that package too. Was wondering what the problem was… I updated it and currently it’s seems to be working well.
Cheers