Varjo Aero and OpenXR - Why no Performance gain over openVR?

[darkman222]

As title says.

It seems like the Varjo Base software comes with an openXR hook for DCS. I havent looked into that for quite a while. I was using SteamVR instead all the time as VarjoXR solution had lower performance.

I have a Pimax Crystal too. And I just did a quick test on my other PC with it. Seems like using PimaxXR has 30 percent performance boost compared to the use with SteamVR.

 

Edited May 28, 2024 by darkman222
Changed Thread title to be more descriptive

[speed-of-heat]

are you confusing OpenXR and OpenXR Toolkit, they are different things, for the Varjo you would likely need GitHub - mbucchia/Varjo-Foveated: An OpenXR API layer to inject foveated rendering in apps using quad views.  VarjoBase has support for OpenXR

[darkman222]

Well, okay. The test with the Pimax helped me to find what might cause my Varjo Aero to show the opposite behavior.

Right now I realized that with the Aero using steamVR it uses Stereo (2 views) to render:

 

But when I switch to openXR it uses Quad views. I guess thats the reason the Aero performs worse with OpenXR

 

Is there a way to make in render only in stereo (2 images) with OpenXR as I dont want to use Dynamic Foveated Render due to various reasons?

 

Edited May 27, 2024 by darkman222

[zildac]

Well, okay. The test with the Pimax helped me to find what might cause my Varjo Aero to show the opposite behavior.
Right now I realized that with the Aero using steamVR it uses Stereo (2 views) to render:
 

But when I switch to openXR it uses Quad views. I guess thats the reason the Aero performs worse with OpenXR

 
Is there a way to make in render only in stereo (2 images) with OpenXR as I dont want to use Dynamic Foveated Render due to various reasons?
 

Out of curiosity, what are the reasons you don't wish to used DFR with your Aero? It's a win win in terms of performance and visuals.

[darkman222]

I tried it. Half a year ago. I play a lot of dogfighting in DCS. And with quad views the labels seem to be rendered only in the high res image. As soon as the label goes into the low resolution area it disappears and I see that. Also due to heavy head turning, the headset slips and eye tracking is lost. Also I can see the high resolution rectangle follow my eye movement, which is distracting.

But it might serve well outside of the special dogfighting needs

It seems like the quad views have more performance impact without DFR than the regular performance you'd get with openVR through steamVR. But as my other test seem to show, in general openXR has higher performance than openVR. So I just need to get rid of the Quad Views to compare both.

I did not think of it earlier, because I did not realize, due to Varjo Base update, or DCS updates I just did not get the Quad views displayed on the monitor any more, so it seemed that OpenXR performs worse than OpenVR, which seems not to be the case and I want to investigate it now.

 

Edited May 27, 2024 by darkman222

[mbucchia]

7 hours ago, darkman222 said:

a way to make in render only in stereo (2 images) with OpenXR as I dont want to use Dynamic Foveated Render due to various reasons

https://github.com/mbucchia/OpenXR-InstanceExtensionsWrapper/releases

Varjo will be adding a toggle in their next release. Until then, the above is the hack.

[darkman222]

6 hours ago, mbucchia said:

Varjo will be adding a toggle in their next release. Until then, the above is the hack.

Thank you Mbucchia. Although Varjo Base now shows the desired stereo render method, the performance to quad view did not change.

Unfortunately the performance of OpenXR compared to OpenVR with SteamVR is in general worse with more microstutters.

( In contrast to that OpenXR on the Pimax performs better than openVR)

Should not native OpenXR on the Aero also deliver superior results compared to OpenVR?

 

Application CPU and GPU are well below 11ms frame time. If I am not mistaken I need 11ms for 90Hz refresh rate. Why does it give that microstutters. The frame rate just goes up and down from 89 fps -> 91 fps and down again.

See that with openXR and SteamVR the graphs are more stable. Except some spikes there is a steady 90 fps in the GPU graph. I was hoping to gain performance with openXR, but the opposite seems the case.

Its the F16 freeflight mission, I always use for testing.

Edited May 28, 2024 by darkman222

[darkman222]

On 5/28/2024 at 5:48 AM, mbucchia said:

https://github.com/mbucchia/OpenXR-InstanceExtensionsWrapper/releases

Varjo will be adding a toggle in their next release. Until then, the above is the hack.

Thanks. Update was released. Can not find the toggle in Varjo Base though. Maybe it was for the other headsets but not the Aero?

[mbucchia]

39 minutes ago, darkman222 said:

Thanks. Update was released. Can not find the toggle in Varjo Base though. Maybe it was for the other headsets but not the Aero?

Better to ask on Varjo Discord, that's where Arch promised me it was going to happen.

[darkman222]

Found the reason. When I run DCS without DFR it runs without Turbo Mode. When I install DFR and disable turbo mode (in the config file) I get the same micro stutters like when I run DCS in OpenXR without DFR. What exactly does this turbo mode do?

When I disable DFR with the no eye tracking option , I can even run it in a higher resolution without  stutters compared to SteamVR.

null

Edited June 10, 2024 by darkman222