[4.11] Keeping Behaviour tree open while play causes Lag

Hi,

Here is a bug I’ve been suffering from that worried me a little bit as at first, I thought that I was doing something wrong with Behaviour Trees.

In fact, it just seem to happen that if you leave the Behaviour Tree Editor window open while launching a VR preview, the BT editor keeps cumulating a growing lag. I don’t really know why though.

Steps:

  • Create a BT
  • Create an EQS query to let’s say search for a Character
  • Call this Query in the BT with a cooldown of 2 seconds
  • Leave the editor open in another tab and launch the VR Preview
  • Observe the fps falling down from the moment the BT runs

If you want more to really be able to see what’s happening. You can profile the run and you will notice that in the profiler there will be GameThread/FrameTime/WorldTickTime/GFTickableTime/FBehaviorTreeEditorTickHelper that’s taking more and more frame-time over time. (up to the point I have it taking about 200ms so far haha)

Hope this can help making UE4 even better :slight_smile:

Cheers.

Hello,

I have been able to reproduce your performance drop and have entered a bug report, UE-30958. Thank you for your report.

Have a great day