Achieve frame sync in UE4's parallel rendering


I’m trying to sync gamethread and drawing thread(RHI thread/rendering thread) , i.e. I want to have updated graphic information before I start next frame and I would like to know when a frame ends as well.

After reading several posts, mainly Low Latency Frame Syncing | Unreal Engine Documentation, it lead me to r.GTSyncType 1 and r.OneFrameThreadLag 0 if you want to get this done.

Is this the right way to go about it? Also, how do I get notified at the end of a frame(after the sync)? I’m not able to find any events to register to.


Im pretty sure thats to lower vsync lag, not that you should have vsync on anyways.

Maybe, but with r.Vsync 0, we can get rid of vsync.
But, r.OneFrameThreadLag says that if it is set to 1 (which is default), you get 1 frame lag, else complete sync. If this is true, why do we need r.GTSyncType and how are these related?