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.

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 ( 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.