search

GameTechDev / PresentMon

Capture and analyze the high-level performance characteristics of graphics applications on Windows.
https://game.intel.com/story/intel-presentmon/
MIT License
1.57k stars 147 forks source link

Weird PresentMode behaviour after cycling dGPU with DXVK #139

Open mirh opened 1 year ago

mirh commented 1 year ago

So.. if you want some extra context and mind grindings check here, otherwise just see below.

Ever since W7, all windowed applications (save perhaps on newer d3d versions with better native presentation modes) should be using Composed: Copy with GPU GDI. And (at least until nvidia added their new driver-side DXGI interop) all normal vulkan applications should be no exception.

Yet, on my 950M optimus laptop, after I disable and re-enable the gpu from device manager something odd happens. The first time (and only then) I run a program with DXVK, I'm getting Hardware: Legacy Copy to front buffer.

This may just be a driver re-initialization quirk (for instance, triggering the UAC secure screen dialog seems to "fix" it) Or it may just be a harmless innocent glitch in Windows (in the sense that it's just "sleepy" the first time and it reports that old mode). That is, nothing that should be of concern directly for PresentMon.

Yet, given certain pathologically bad performance numbers I'm getting, I feel like a third option might be in the making: that the reporting of Composed: Copy with GPU GDI is actually wrong. I don't know how I could bisect this problem more (and my brain already hurts after so much analyses) so I was hoping you could have some better clues.

JeffersonMontgomery-Intel commented 11 months ago

I'm not really sure what could be going wrong here. It's certainly possible presentmon is getting confused through this procedure if it's getting events in unexpected patterns.

I'm not sure what you mean by "bad" performance numbers; the app could be getting routed to igpu or even warp or something?