Moving the Sun & Using Timelines causes lag

Development Rendering
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1

Hi there, following this tutorial (but setting the sun’s rotation speed much slower) causes nearly no lag when used by itself.

Separately, if I have a bunch of actors following a spline using a timeline uses little enough CPU.

(Note, for repro, the timelines are 0.f-1.f along the x axis and 0.f-1.f along the y axis, y axis is percentage completion of the spline and x axis is percentage completion of the allowed time, so the timeline has .SetPlayRate((1 / BestFinishTime) * (FinishTime / BestFinishTime))

If I do one or the other of the above things, the game runs at 60FPS(+) with no issues. However, if I do both at the same time, then the game stalls the CPU with a bunch of “wait for event xx” (oh and GPU use drops dramatically too…?)

I have two stat files which I can attach but are too large… (9MB and 11MB). If it is possible for me to email somebody with the stat files please let me know.

Note: It cannot be that the actors I am adding to the scene are too complicated as they can be added and no issues exist until I start running the Timelines.

2

Hi vikhik,

Could you supply a small test project that showcases the issue? Please also include repro steps as well.

3

I’ll see what I can do tomorrow, thanks :slight_smile:

4

I cannot replicate the issue…

Unfortunately, even with pulling down the old version of the repo it appears that I have a “wait” every time I recapture sky on the sky light.

However, I still have the old logs where the wait only happened once my race had begun.

5

I’m sorry I am misunderstanding. Is the lag issue still happening?

6

Hi TJ, I have narrowed it down and it turns out that I was merely not moving the sun when I was not racing. (I failed to hook up a False branch exec back to the output of a function)

Moving the sun, recapturing the sky, etc., rightfully causes the correct amount of wait while everything computes.

Turns out that I was just being silly, please close this bug report!

7

However, if you follow the tutorial linked above and use the “stat detailed” command twice, followed by “stat FPS” you get some very weird stats.

i.e. Draw/GPU are very very lose (<2ms) and CPU is medium (<10ms) but the Frame time is very high (>20ms)