UI Rendering Slowness (Sync Point?)

[herocrab]

Release Type: Official Release

Version: 3.0 and 3.1

Platform(s): Windows

Describe the bug
UI Rendering on systems with slower processors (previous generations, a couple years old) but still very capable graphics cards experience frame rate/update rate loss when rendering Xenko UI. Toggling the UI off on these systems and the frame rate/update rate resumes to normal (or as fast as it can when running with the profiler). These are not significant UI implementations, a simple player name and HP bar player panel above a character and a kill log scroll viewer in the lower left of the screen (no greater than 8 entries).

Render groups 1-3 bypass the forward renderer and are rendered in their own single stage renderer or a shared renderer (both have been tested). Also tested with the default compositor, same results.

I've had another developer take a look at the implementations and the logic is sound, no unnecessary UI changes or updates per tick.

A number of things have been tested:

• Font type (SDF, vs Offline Rasterized, vs Runtime Rasterized)
• Various compositor configurations with various stages.

To Reproduce
Steps to reproduce the behavior:

1. Create a game
2. Add UI to it, scroll viewers, etc
3. Profile the game on various platforms

Expected behavior
Minimal UI shouldn't cause such a significant performance impact and limits release of the game.

Additional notes
If one of the engine developers are interested I can share out my game to them, however it includes all the binaries so will be at download.

Issue may also somehow be related to #101

[herocrab]

Full UI:

No Scroll Viewer:

No Scroll Viewer, No Hud:

No Scroll Viewer, No Hud, No Player Panel:

What is ~1.5-2 ms on my system (Intel I7-8750H) is 10-15 ms on other systems with reasonable hardware.

There is some wait or sync point issue occurring between CPU and GPU for UI, whether it's the "picker" or something else I am not aware; it is currently above my skill set to debug... I fear it wouldn't be wise to release a game into the wild using Xenko UI with this occurring.

Let me know if I can be of further service.

[makotech222]

@DevJarmo Try throwing in more UI elements in the world. Also try moving your camera closer and farther away from those elements, if you can.

[xen2]

I have ~1 msec for GameMenu sample. Can you let me know your timing for reference? If yours is fast too, maybe I might need a repro sample.

Also, I heard (on discord) about timing like 10~30 msec but this doesn't seem to be the case here?
You mention 10/15 msec on slower system but are you referring to slower desktop, or mobile?

[makotech222]

Hmm, on the game I was working on that had this problem, it seems to have been fixed since xenko v 3.0.0.3. I just tested again today with the profiler and on latest 3.1 beta, and I don't get the same issues I had before. FPS maintains around 120fps. I wonder if it was a vulkan issue maybe? I tried setting my project to vulkan (my default in 3.0), but have weird issue with gamepad not being found, so game throws exception. Don't want to dig any further on it though.

[profan]

@xen2 for reference, same scene on my system (i7 920 + R9 390) also a release build

Full UI:

No Scroll Viewer:

No Scroll Viewer, No HUD:

No Scroll Viewer, No HUD, No Player Panel:

[xen2]

@profan @DevJarmo Ha yes, much worse for @profan case
What are your respective CPU/GPU?

By any chance, easy for you to create a repro project (i.e. small project with just the UI slow part)?

[herocrab]

My spec's are:

8th Generation Intel® Core™ i7-8750H Processor
Windows 10 Home 64bit English
8GB, 2x4GB, DDR4, 2666MHz
NVIDIA® GeForce® GTX 1050 4GB GDDR5

I have no problems with UI while plugged in (Laptop), though after profan had the issue I saw it on a number of other systems during a demonstration/test. I am also able to repo the issue when I run on battery power and my CPU is rate limited. Fairly certain the issue is on the CPU side. During the demonstration, In all cases, I could just toggle off the scroll viewer and/or game UI and the update time would generally drop down below 16 ms... the boxes would have no problems with 3d rendering, shadows, or particle effects.

@xen2 Interesting thing, I have a couple of older Alienware Alpha I3's with Nvidia's and they do not have the issue (at least not impacting the update rate above 16ms). Could the issue be Xenko UI rendering with Radeon graphics cards? I believe the systems in the demo which were having slowness may have also been Radeon, I will reach out and inquire and return with infos.

[herocrab]

Other systems that experienced this were:

AMD FX6300
120 GB SSD
8GB Ram 2100MHZ
Radeon R370 4GB <--- Issue may be related to Radeon graphics cards.

[herocrab]

@xen2 On the Xenko UI Sample I have <1 ms draw. I will ask @profan if he can test the sample.

Profan said he will test with the Xenko sample after he returns on the 31st.

[profan]

@xen2 as promised on my system (CPU: i7 920, GPU: R9 390)

it generally oscillates between 7-8ms to 12ms, so.. yeah 👀 (sorry about the delay, more things got in the way)

[phr00t]

@profan can you check the UI on my fork to see if you experience the same problem with Vulkan?