Constant terrain stutter on MT

[EbonySeraphim]

I'm not an expert in VR matters, but how do you remove the idea that the CPU is the culprit? DCS stutters can be a lot; I found serious stutters coming from both DCS-BIOS and DCS-ExportScripts -- I had to turn those off. VoiceAttack, SRS, TacView, VPCLinkTool, and DCS ScratchPad were all fine.

I know you describe it as "terrain stutters" but honestly, the stuttering I've seen in general with this game have generally been most observable on terrain to the naked eye but is most certainly the entire game. Without stats from a profiling tool like MSI Afterburner, you don't know what you have.

[Sile]

vor 57 Minuten schrieb EbonySeraphim:

I'm not an expert in VR matters, but how do you remove the idea that the CPU is the culprit? DCS stutters can be a lot; I found serious stutters coming from both DCS-BIOS and DCS-ExportScripts -- I had to turn those off. VoiceAttack, SRS, TacView, VPCLinkTool, and DCS ScratchPad were all fine.

I know you describe it as "terrain stutters" but honestly, the stuttering I've seen in general with this game have generally been most observable on terrain to the naked eye but is most certainly the entire game. Without stats from a profiling tool like MSI Afterburner, you don't know what you have.

I remove the CPU idea because it's perfectly smooth with the ST client. And DCS doesn't stutter for me in 2D, does it for you?
So something is very different with the MT Client. And we post our observation in "Multi-Threading Bug Reports (Temp) " and hope ED maybe will look at it.

Thank you @fab.13. Will try the registry trick later.

[EbonySeraphim]

5 hours ago, Sile said:

I remove the CPU idea because it's perfectly smooth with the ST client. And DCS doesn't stutter for me in 2D, does it for you?
So something is very different with the MT Client. And we post our observation in "Multi-Threading Bug Reports (Temp) " and hope ED maybe will look at it.

Thank you @fab.13. Will try the registry trick later.

The stuttering may not be stuttering in ST because your FPS is considerably lower to begin with. I didn't notice stuttering until MT made the performance drop to my 1% lows massive. But as I did a ton of profiling, the performance issue was very much there in ST as well. Debugging performance stuttering is a difficult problem to solve, even for an actual software engineer. You might get lucky trying random things, and have a fix in a few days. Or take a steady and process of elimination path and have a confident identification of the problem with a solution eventually.

[fab.13]

Hello

The need to have as much as possible CPU ressources free seems to be  more critical in MT version

For example, i have much stutter when windows update run in background ( take 10% cpu try to update that i have blocked with some hacks) Killing the process deleted my DCS stutter ( not sporadic micro stutter )

So CPU Usage should be as lower as possible before starting DCS ( true for many years ago )

[Sile]

Hypothesis.
The MT client uses so much CPU Resources (it does from looking at the resources in task manager), that secondary processes like OpenXR chain, Oculus Link Encoding, ... get stalled?
Whereas the ST client leaves enough threads/cores/headroom for the secondary VR stuff.

Edited May 22, 2023 by Sile

[fab.13]

Yes

I suggest you to check cpu usage before starting DCS.

mine is 1% and i have only sporadic micro stutter with free flight and lowest settings ( as written in patch notes )

[Sile]

Cpu usage before DCS startup is fine. < 1%. No thermal throttling, etc.

DCS FPS graph shows a constant line at 72 fps (72 Hz setting used) on ST and MT. No single spike. Even at 90 Hz i manage to get a constant frametime without MSAA.

MT has microstutters. Maybe sporadic. Not showing in fps graph. ST doesn‘t. 

Reported and out. 

Thank you all.

Edited May 22, 2023 by Sile

[fab.13]

I agree

But how could we help ED to analyse this issue ?

Mesure Frame Drop ?

Mesure FrameTime ( cpu, gpu ) ?

Providing short track ?

ED team to provide a status about the 'sporadic stutter' as written in patch notes when MT was released ?
 

Because some people can meet microstutter with MT version ( me included ).
And upgrading hardware may be not a solution as we can read in MT forum.

Microstutter could take a long time to be solved if it is not "Reported"

Edited May 22, 2023 by fab.13

[Munkwolf]

For those having microstutters with a G2 and nvidia cards, could you try something for me?

I've been going through a/b testing different settings using the hornet caucasus free flight mission. Continously rolling and looking at the ground.

I was having the terrain stutters. Tried the most recommended things.. slow repair, empty saved games, hyperthreading on/off, hags on/off, nvidia control panel settings.. nothing was making too big of a difference.

One setting that is though, is the 'Disable NVIDIA Optical Flow Acceleration on RTX cards' in OpenXR Tools for WMR. Disabling it seems to make a big difference for me. Still see 'CPU bound (main thread)', but the terrain stutters seem much better.

I've toggled the setting on/off a half dozen times now and rolled around til i was dizzy, and seems consistently better with that disable setting checked.

Has that been suggested/tried already? I haven't seen it mentioned. Can anyone else with a stubborn terrain stutter issue on nvidia with a G2 try it out?

11900kf @ 5ghz, asus rog 3090, 64GB

Edited May 23, 2023 by Munkwolf

[Geoman]

@Munkwolf: I tried your setting and did my usual morning routine (Hornet River Run and Nalchik landing) - the stutter disappeared!

[BIGNEWY]

Something else that has helped some people. 

NVIDIA control panel > Low latency mode > Ultra 

worth trying if you are still seeing issues

 

[Sile]

vor 7 Stunden schrieb BIGNEWY:

Something else that has helped some people. 

NVIDIA control panel > Low latency mode > Ultra 

worth trying if you are still seeing issues

 

Thanks. Unfortunately this doesnˋt work for me. What works is setting SteamVR as OpenXR Runtime and H.A.G.S. off. Smooth.

[Munkwolf]

28 minutes ago, Sile said:

Thanks. Unfortunately this doesnˋt work for me. What works is setting SteamVR as OpenXR Runtime and H.A.G.S. off. Smooth.

Same with the latency setting. I'm running native openxr and not via steamvr. I feel like the NVIDIA latency mode works against getting smooth frames - for smoothness, don't we want frames over latency? Prioritizing latency over frames seems like it'd introduce more stutter?

What's working best for me is having that latency setting off, and doing the 'disable optical flow accel' setting in openxr tools.

This morning someone pointed me to this post by mbucchia going over those openxr tools settings in more detail: https://forums.flightsimulator.com/t/openxr-tools-for-windows-mixed-reality-update-in-the-store-4-14/586988

Based on that post, later today i'm going to try re-enabling HAGS and turning on the 'prefer framerate over latency' option in openxr tools - mbucchia's post says it's 'highly recommended' (with HAGS on) and similar to turbo mode in openxr toolkit.

Edited May 23, 2023 by Munkwolf

[St4rgun]

IMHO for the best visuals with OpenXR please DISABLE motion reprojection entirely in the settings and enable "turbo mode" in OpenXR toolkit. With the current OB it produces pretty high framerates with minimal stuttering, very smooth experience.

[Temetre]

vor 3 Stunden schrieb St4rgun:

IMHO for the best visuals with OpenXR please DISABLE motion reprojection entirely in the settings and enable "turbo mode" in OpenXR toolkit. With the current OB it produces pretty high framerates with minimal stuttering, very smooth experience.

For me turbo mode just breaks things and kills framerate. Its a pretty unreliable feature with limited use^^

[KoN]

On 5/24/2023 at 7:32 AM, St4rgun said:

IMHO for the best visuals with OpenXR please DISABLE motion reprojection entirely in the settings and enable "turbo mode" in OpenXR toolkit. With the current OB it produces pretty high framerates with minimal stuttering, very smooth experience.

Will test today. Stuttering over the last few days . VR.

[fab.13]

Hello,

I played with my VR bench track replay in order to deal with DCS MT micro-stutter i can meet ( core I5 10600k 1080ti 48Gb RAM Quest 2 )

What a surprise that, when enabling shadow, most of micro stutter disappear !

I had disabled shadow in order to get better perfo in the past,
and now, i have to restore shadow to get smooth VR playing in DCS MT...

Here is a link that speak about the same observation than me :
https://www.v303rdfightergroup.com/index.php?threads/getting-the-most-out-of-dcs-multithreading.756/#post-2016

So, for people that meet micro stutter in DCS MT
try putting some shadow setting or change shadow setting
( Shadow setting and Terrain shadow, no Blur or cokpit shadow...)

I joined a track replay ( Mirage F1 ) for people that want to test in VR :
- look on right side and left side in the 2 first minutes of the replay
- if you see micro stutter ( right side in my case ), try changing shadow setting
 

test2.trk

Edited May 30, 2023 by fab.13

[Ramtin]

On 5/23/2023 at 2:02 AM, Munkwolf said:

For those having microstutters with a G2 and nvidia cards, could you try something for me?

I've been going through a/b testing different settings using the hornet caucasus free flight mission. Continously rolling and looking at the ground.

I was having the terrain stutters. Tried the most recommended things.. slow repair, empty saved games, hyperthreading on/off, hags on/off, nvidia control panel settings.. nothing was making too big of a difference.

One setting that is though, is the 'Disable NVIDIA Optical Flow Acceleration on RTX cards' in OpenXR Tools for WMR. Disabling it seems to make a big difference for me. Still see 'CPU bound (main thread)', but the terrain stutters seem much better.

I've toggled the setting on/off a half dozen times now and rolled around til i was dizzy, and seems consistently better with that disable setting checked.

Has that been suggested/tried already? I haven't seen it mentioned. Can anyone else with a stubborn terrain stutter issue on nvidia with a G2 try it out?

11900kf @ 5ghz, asus rog 3090, 64GB

 

 

I will try this one for sure and report back. I too had this stuttering issues when looking sideways in MT mode. 

Edited June 1, 2023 by Ramtin

[altyee]

I had a similar issue with some slight differences.

I used an Intel A770 GPU to run DCS on a new 4k165 screen (didn't have this problem with my old 2k60 screen) and found the exact same problem with terrain stuttering, while my FPS is around 55-60 and anything inside the cockpit is perfectly smooth. The difference is that I tried ST and the stuttering is still there. Even when lowering settings to all low 1080P, I still manage to reproduce the stuttering above dense areas on the Marianas map (MT). The stuttering is definitely not graphics performance-related (still stutters at 120+fps). Intel GPUs have a bad reputation for their drivers so that could be it though. I also found that lowering the terrain texture setting to "low" will help a little bit, but does not make the game any more playable. 

Spent a good afternoon tweaking and testing with different settings and finally found a way to mitigate the issue for me. I changed the "maxfps=180" to "maxfps=60" in  "..../DCSWorld/Config/graphics.lua" and found the stuttering to be much better (if not completely disappears, I didn't do too many tests to confirm).

I guess the stuttering has something to do with the display refresh rate vs. your actual fps vs. the fps on the other threads that handle the terrain. Probably any significant difference between those three will make the terrain stutter (?). Well, that is for ED to figure out. 

 

[fab.13]

Hello,

did anybody have tested some Shadows settings versus stutter ?

( see my post above)

[altyee]

1 hour ago, fab.13 said:

Hello,

did anybody have tested some Shadows settings versus stutter ?

( see my post above)

I tried turning on/off both shadow options but the stuttering was still there (the environment outside of the cockpit is stuttering, but the plane on F2 view is perfectly smooth, on both ST and MT). But again I wasn't using VR so it might be a different problem. Thanks for the suggestion anyways!

[Sile]

vor 21 Stunden schrieb fab.13:

Hello,

did anybody have tested some Shadows settings versus stutter ?

( see my post above)

Still on my list. I had no time to test, yet.

[fab.13]

I forgot to say that "Shadows" on "Low" and "Terrain Shadows" on "Default"  give the best results on my side.

The micro-stutter that i still can see are on Rolling Plane or Moving Head quickly ( left-right cockpit view are smooth for now with shadows ).

Edited June 3, 2023 by fab.13

[MoleUK]

On 5/23/2023 at 9:52 AM, BIGNEWY said:

Something else that has helped some people. 

NVIDIA control panel > Low latency mode > Ultra 

worth trying if you are still seeing issues

 

Running at (very) similar resolutions on the same DCS settings on the same headset, I can get varying results. When playing via Oculus link with ASW enabled, I have no terrain stutter when looking sideways. Regardless of whether or not ASW is currently active. This is on the OpenXR runtime.

However, when running via VD on the oculus runtime, looking sideways results in terrain stutter as it goes by.

This is on the MT build with the exact same in-game and nvidia control panel settings. I had actually gotten used to the terrain stutter so it was a shock when switching over to link/openXR totally eliminated it again.

I can see no frametime spikes or fps drops while the terrain stutters. Everything inside the cockpit remains smooth while the terrain stutters by, it's definitely odd.

I would have guessed that it's runtime related, but I have seen the same terrain stutter on flatscreen footage at times.

It's almost like the terrain is being rendered at a different (half?) fps from the cockpit/plane.

I have seen that some distant planes and trains are rendered at reduce fps rates at times since the MT release. You can see them stutter across the screen at very long distances.

I assume this is an intentional optimisation step, perhaps the terrain is also mistakenly falling under the same bracket sometimes? Or if it's not an intenional optimisation step, it's a wider problem/bug.

Edited June 3, 2023 by MoleUK

[Sile]

Checking back in. 

Enabling Tubo Mode in OpenXR Toolkit did it for me. Now OpenXR in MT via Occulus Runtime is smooth. 
(I was finally able to enable Turbo Mode in the DCS main menu, since enabling it inflight crashed DCS for me)

My stutters/jitters were not visible in the frametime graph of DCS (RCTRL+Pause) it was always a constant line, so somehow turbo mode fixed the timing i guess.

So:

:: ST - smooth with any API / Runtime

:: MT OpenXR (Occulus): smooth with Turbo Mode ON  (HAGS off seems to be better but no big difference)
:: MT OpenXR (Steam): smooth (HAGS off definitively better)

Just to give you all some options for testing. And in reference to the OpenXR/SteamVR/anything poll in the VR section: Please ED, leave us some options.

P.S.: @fab.13Shadows didn't change anything for me. Maybe my problem was a bit different. But thanks and maybe it helps someone else.

Edited June 6, 2023 by Sile