DPC latency issue

[dsavovic25]

DPC/ISR latency can be a deep rabbit hole.

Did you already disable in bios all c-states (including package) that aren't c0 or c1?

Did you already modify a clone of the high performance power profile (easiest way to clone it is to just install process lasso to get the bitsum power profile) to expose the setting to disable idling (google: powersettingsexplorer)?

If you didn't do those things already, just try those first. The 2nd thing will for sure fix the issue, but don't use it while idling -- switch to it only when you really need to, like when actually gaming or doing professional audio mixing.

Good point about the bios settings, I've have completely forgot that I have disabled Intel C-state, HPET and Intel SpeedStep.

[daemonjax]

Good point about the bios settings, I've have completely forgot that I have disabled Intel C-state, HPET and Intel SpeedStep.

There are specific c-states. C0, C1, C2, C3, C6 (core parking), etc. There's also package c-states.

Good motherboards expose all that in bios.

Not all motherboards do.

If your motherboard doesn't expose disabling _specific_ c-states (including the "package" ones), then I would at least try the thing I mentioned about using powersettingsexplorer to disable all c-states except for c0 within a clone of the windows high performance power plan profile. While your PC is running that profile (all cores in c0 states) dpc latency issues aren't even a thing that can happen (well, I guess a terrible driver could still do it, but you'd figure it would just bsod your machine instead).

[dsavovic25]

I'm not sure about Valorant, but CS2 is extremely GPU intensive now.
Especially even more so since you're on a Polaris AMD GPU, where the D3D11 implementation is notorious for being terrible.

I've heard enough. Thanks for your time and effort in trying to help me out.

[dsavovic25]

Good point about the bios settings, I've have completely forgot that I have disabled Intel C-state, HPET and Intel SpeedStep.

There are specific c-states. C0, C1, C2, C3, C6 (core parking), etc. There's also package c-states.

Good motherboards expose all that in bios.

Not all motherboards do.

If your motherboard doesn't expose disabling _specific_ c-states (including the "package" ones), then I would at least try the thing I mentioned about using powersettingsexplorer to disable all c-states except for c0 within a clone of the windows high performance power plan profile. While your PC is running that profile (all cores in c0 states) dpc latency issues aren't even a thing that can happen (well, I guess a terrible driver could still do it, but you'd figure it would just bsod your machine instead).

I've disabled cpu idle and it did kinda made a big improvements. Thanks. Very weird, that is roughly 50% of the latency ntoskrnl.exe actually had before. Small tip is to be kinda careful with this option. If you disable it cpu utilization goes to constant 100% usage.

[JimCarry]

I'm not sure about Valorant, but CS2 is extremely GPU intensive now.
Especially even more so since you're on a Polaris AMD GPU, where the D3D11 implementation is notorious for being terrible.

I've heard enough. Thanks for your time and effort in trying to help me out.

+1

[daemonjax]

If you disable it cpu utilization goes to constant 100% usage.

Well, not really.

It only appears that way when looking at cpu usage using a program that simply calculates core usage by the time spent in the c0 state. So if it's in the c0 state 100% of the time, it will report 100% core usage. But, that's sort of a lie.

While it's true that by not entering the c1 or lower idle states, it's using more power which increases thermals somewhat... BUT what you're not experiencing is increased thermals from doing actual work (flipping states from 0 to 1 and back again). So, you will not experience so much increased thermals as if you were ACTUALLY running a cpu at 100% by giving it that much work to do (e.g. running prime95 worker threads on all cores).

In practice, it's a much more modest increase in temps when idling at the desktop -- and anyways I repeatedly said don't do this btw.

Furthermore, disabling c1 and deeper c-states when already using a cpu-intensive program (such as a game) will result in a negligible increase in temperature when compared to allowing c1 and deeper c-states in the same scenario.

[dsavovic25]

If you disable it cpu utilization goes to constant 100% usage.

Well, not really.

It only appears that way when looking at cpu usage using a program that simply calculates core usage by the time spent in the c0 state. So if it's in the c0 state 100% of the time, it will report 100% core usage. But, that's a lie.

It's true that by not entering the c1 or lower idle states, it's using more power which increases thermals... BUT what you're not experiencing is increased thermals from doing actual work (flipping states from 0 to 1 and back again). So, you will not experience so much increased thermals as if you were ACTUALLY running a cpu at 100% by giving it that much work to do (e.g. running prime95 worker threads on all cores).

In practice, it's a much more modest increase in temps when idling at the desktop -- and anyways I repeatedly said don't do this btw.

Furthermore, disabling c1 and deeper c-states when already using a cpu-intensive program (such as a game) will result in a negligible increase in temperature when compared to allowing c1 and deeper c-states in the same scenario.

Makes sense, thanks for the clarification.

[JimCarry]

You dont need powersettings explorer,i made these scripts long time ago,i used to use them to disable idle before going into cs2, and then enable idle when i am done,but now i dont disable idle because i have stock cooler,but if op wants to use it.you just make 2 bats files,and put in the first two in one bat and the other two in second bat.


powercfg.exe /setacvalueindex SCHEME_CURRENT SUB_PROCESSOR IdleDisable 0
powercfg.exe /setactive SCHEME_CURRENT

powercfg.exe /setacvalueindex SCHEME_CURRENT SUB_PROCESSOR IdleDisable 1
powercfg.exe /setactive SCHEME_CURRENT

[JimCarry]

Processor Idle demote and promote are set to 100% in power plan"

No, that's different.

There are MANY power plan settings that are hidden by default. To expose them, you use powersetttingsexplorer:

https://forums.guru3d.com/threads/windo ... ty.416058/

There is one in particular that's useful (everything else... not really useful, don't bother): "processor idle disable"

It's either enabled or disabled. When you set it to "disable idle" only the c0 c-state is available to your cpu. Doing it within a cloned power plan let's you easily enable/disable it as needed. Audio engineers mixing studio audio have legit dpc latency concerns, and they do this... on laptops. I'm just saying this is a viable option if you don't want to go down this rabbit hole. Or, you at least do this as a first step to find out if the issue you're experiencing even really truly is a dpc latency issue... before going down this rabbit hole.

[dsavovic25]

You dont need powersettings explorer,i made these scripts long time ago,i used to use them to disable idle before going into cs2, and then enable idle when i am done,but now i dont disable idle because i have stock cooler,but if op wants to use it.you just make 2 bats files,and put in the first two in one bat and the other two in second bat.


powercfg.exe /setacvalueindex SCHEME_CURRENT SUB_PROCESSOR IdleDisable 0
powercfg.exe /setactive SCHEME_CURRENT

powercfg.exe /setacvalueindex SCHEME_CURRENT SUB_PROCESSOR IdleDisable 1
powercfg.exe /setactive SCHEME_CURRENT

Thanks for the script.