Does "FPS Limit" Still works for Win10 for DX11 VR applications?

[Azlun_X_]

I want to use GPA Ctrl+Alt+G hot key to controll the GPU rendering rate and output rate to HUD, HTC VIVE,

can I? ref:

Target:

Windows 10 build 10586, 64-bit DEP enabled
Num Processors: 8
Memory: 16319MB
System BIOS: AMI A0.07 (10/26/2015)
Driver 0:
     Device: NVIDIA GeForce GTX 980 Ti
     Provider: NVIDIA
     Date: 6-2-2016
     Version: 10.18.13.6839
     VendorId: 10de
     ProductId: 17c8
     Stepping: a1
     No support for GPA Instrumentation
Install directory: C:\Program Files\IntelSWTools\GPA_16.1\
Version: 16.1.282401
Current user is in Administrators group: YES
Current Graphics Performance Analyzers 2016 R1 (16.1.282401)
Secure Boot/Trusted Boot is Disabled
"Auto-detect launched applications" is On

[Azlun_X_]

My GPU driver is latest, Does "   No support for GPA Instrumentation" blocking me?

Can I have a way to make "Support for GPA Instrumentation"  for NVDIA GPUs?

[Azlun_X_]

I found my problem, but still have lag in HTC VIVE theBLU app;

I should disconnect remote GPA system analyzer client if I want to enable " FPS limit" feature locally on target machine;

another method is using remote GPA system analyzer client "FPS limit" options on left list to active it;

Problem is,  While HUD Options I have set is60fps while to VIVE support 90fps.

after enabled " FPS limit", I found the FPS become 45-75-45-75-45-... average is 60fps, this bring too much lag,

anybody have solution to make FPS smoother? 

As reference, with the same tools, but change to Application Lucky' Tale on Oculus Rift CV1 Hardware, the FPS is 59-60-60-59-60...quite smooth.

[Seth_S_Intel · Accepted solution]

Hi Azlun, 

Sorry that you are running into these issues. 

Do you see the FPS instability only when GPA is attached? 

Also, we just started to partially support VR, but often when you see frame rate instability like that it's usually some type of VSync problem. Since the Vive expects 90 fps and not lower and you are only sending 60 at best, the timing is off for VSync to pick up a new frame buffer.  But this is just a guess.  

Also, as for NVidia GPUs, you should still be able to analyze but you will have far fewer metrics as we don't have access to the NVidia driver.  You still should be able to do FPS limit though because we do querry the frame limit.  

Best,

Seth

[Azlun_X_]

Thank you very much for your feedback, You are right, FPS 45-75 leg issue only happen while GPA is attached to VIVE apps, but it is NOT happen while I use GPA on Oculus Rift, so I think there also something relative to VIVE framework- SteamVR,

I just raised a support case to Steam with system log to see do they awake about GPA issue. hope both Intel and Steam note this and investing it for futher better usage for GPA.

[Azlun_X_]

How can I understand below image status? the headset mirror from Steam VR is always 45fps no matter it is 90fps or 45fps at host.I am doubt that 45fps is bug since I feel very smooth on the headset while app window display 90fps

[Seth_S_Intel]

Hmm, very interesting.  When it says 45fps on the target, does it feel laggy?

I'm wondering if it might be a bug with how we are reporting the FPS on the host.  

Best,

Seth

[Azlun_X_]

There are two cases beside the 45-75fps saturation, in my two screenshots shared.

1st screenshots is I use the SteamVR default renderTargetMultiplier :1.0 configuration, the App Window is 90fps, but Headset Mirror is 45fps,I do NOT see any lag, it is smooth, since this is the default user experience. that confusing me why GPA display 45fps on it.

2nd screenshots is I use the SteamVR SuperSampling renderTargetMultiplier :2.0 configuration, the App Window is 45fps, and Headset Mirror is 45fps,I feel Tiny lag while focus on a object nearby and moving head fast. I think that is the side-effect of supersampling I can understand.

I want trying to find some other tools such as NVDIA GFE-ShadowPlay to label FPS on headset Mirror screen, but fail. If you know some tools or logging method can do it, please let me know.

[STANISLAV_V_Intel]

Hi Azlun,

GPA calculates FPS based on number of Present calls over second. So I'm pretty sure that HTC Vive mirror image is actually 45 FPS while the game is actually 90 FPS. At least if you rely on Present calls as a marker of frame end.

Why it's so is an open question for which I don't have a clear answer. My assumption is that HTC vive have some SW or HW backdoor method to retrieve frame buffer from the actual HW and does that with some fixed frequency (aka 45FPS).

Would be interesting to increase super sampling option further more and look how mirror FPS change in that case. Wouldn't be surprised to still see 45 FPS.