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alvr-org / ALVR

Stream VR games from your PC to your headset via Wi-Fi
MIT License
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Low GPU utilization when "Optimize game latency" turn on #2326

Open G00dog opened 4 weeks ago

G00dog commented 4 weeks ago

When I enable the "Optimize game latency", my FPS drops, and GPU utilization decreases. When I disable "Optimize game latency," FPS is stable, and GPU utilization increases, but the latency becomes inconsistent, making it difficult to use.

The picture is the difference when looking at exactly the same place. optimize on optimize off Maybe it's the same issue. [(https://github.com/alvr-org/ALVR/issues/1901)]

Is there a solution for this problem?

Description

General Troubleshooting

Environment

Hardware

CPU : Intel(R) Xeon(R) Gold 6238R CPU @ 2.20GHz

GPU : NVIDIA RTX A6000 X2

GPU Driver Version : 552.74

Audio :

Installation

ALVR Version : 20.5

ALVR Settings File :

SteamVR Version : 2.74

Install Type:

OS Name and Version (winver on Windows or grep PRETTY_NAME /etc/os-release on most Linux distributions): Window 10

zarik5 commented 4 weeks ago

Can you show the latency and fps graphs for both with and without "optimize game render latency"?

G00dog commented 4 weeks ago

optimize on optimize off

Looks like a needle is turning off the optimization game render latency

zarik5 commented 4 weeks ago

Yeah that bug seems to be caused by SteamVR not respecting the framerate we set. To be honest though, disabling that setting is wrong usage of the OpenVR driver API (the implementation details are quite complex). This works on Windows, but on Linux the implementation is completely different and that part of the code is skipped altogether.

So I think at this point we should remove the option as forcing it to true.

Anyway your first graph looks perfect (apart from the staircase issue, which will be fixed). I don't see any fps drop.

Vixea commented 4 weeks ago

I think the issue is frame pacing here if you look at the graph even if the avg server fps is the clients I wouldn't be surprised if those small dips are noticeable?

Vixea commented 4 weeks ago

Anyway I don't get the lower util as being a bug its not its like complaining your browser isn't using 100% of your cpu

G00dog commented 3 weeks ago
optimize on optimize off

This image shows the difference in frame drops when 'Optimize Game Render Latency' is turned on versus turned off. I thought that if the GPU usage was as high with 'Optimize Game Render Latency' turned on as it is when it's turned off, it might result in better performance. (Please understand that I’m not very knowledgeable about computers.)