[SOLVED] Stuttering/hitching after BIOS update

[lordof7]

Gaming on Gentoo with Steam has been working well until yesterday when I updated my BIOS to mitigate the Intel 13/14gen degradation issue. I'm now having microstuttering or hitching while gaming, specifically in Graveyard Keeper. (I've also noticed loading screen issues in Cuphead.) Following the BIOS update I did take some time to retune my undervolt, which was stable in Win11 testing. I have tried Graveyard Keeper in Win11, and it runs well with no stuttering. Cinbench R23 and 3DMark Timespy results in win11 were similar to those with the previous BIOS. I have not updated anything on my Gentoo machine since the BIOS update.

Here's what I've tried, none of which reduced the stuttering in gentoo:
Enable disable Retuneable BAR
Enable disable hyperthreading
Enable disable AMD Freesync
Tried all of my old undervolt settings (all stable in windows with Cinebench R23, OCCT CPU and linkpak tests)
Reduced my mouse polling rate to 125Hz with piper
Changed monitor refresh from 120hz to 60hz
Deleted the shader cache for this game
Checked game file integrity (ok)

I have not noticed anything amiss in dmesg or Xorg logs.

Any thoughts? I'd rather not roll back the BIOS.

System info: Intel 13600K, MSI Z690 Pro Wifi, 32GB GSKILL 5600, AMD RX 6700XT

EDIT: I'll mark as solved - see second post down for the details of setting the Intel P-state governor to "performance".

[lordof7]

Some more info:
kernel: 6.7.12-gentoo (6.6.x had issue with GPU undervolt, haven't tried 6.10.x yet)
Mesa 24.1.6
X11 1.8.10
xorg-server 21.1.13-r1
xfce4 4.18-r1

key lines from Make.conf:

Code: Select all

COMMON_FLAGS="-march=alderlake -O2 -pipe"
CFLAGS="${COMMON_FLAGS}"
CXXFLAGS="${COMMON_FLAGS}"
FCFLAGS="${COMMON_FLAGS}"
FFLAGS="${COMMON_FLAGS}"
MAKEOPTS="-j8"

CPU_FLAGS_X86="aes avx avx2 f16c fma3 mmx mmxext pclmul popcnt rdrand sha sse sse2 sse3 sse4_1 sse4_2 ssse3"

USE="gtk -gnome -kde -qt3 -qt4 -qt5 X"

VIDEO_CARDS="amdgpu radeonsi"

[lordof7]

I do believe I've found a solution to this issue: changing the Intel p_state governor to "performance" resolved the hitching. I recall this being a theory behind microstuttering on windows: the changing processor states were to blame.

If anyone wants to try, here's my notes. Not sure if it applies to AMD cpu users or even other Intel CPUs beyond the Raptor Lake. Here's the kernel documentation:
https://www.kernel.org/doc/html/latest/ ... state.html
The gentoo wiki page is here, although I admit I was a bit confused (turns out the intel p_state driver has similar name to cpufreq but different behavior. CPU frequencies DO change under both powersave and performance governors (really, driver algorithms)). I believe the wiki is a bit out of date as ondemand is no longer a default (or, at least not when the intel pstate driver is selected.)
https://wiki.gentoo.org/wiki/Power_management/Processor

To confirm driver:

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$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver
intel_pstate
intel_pstate ...

To view intel algorithm if using p_state:

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$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
powersave
powersave ...

To change to performance (as root)

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# echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

To change back to powersave (as root)

Code: Select all

# echo "powersave" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

I did notice that the frequencies did change around, and were overall higher on performance. Voltage was higher (but within my tuning parameters). Coretemp did not seem to change, and didn't seem any hotter in some short testing in Graveyard Keeper. All microstuttering/hitching was gone.

I will note that I did not observe this hitching in other games I tried (Blaspehmous, Valheim), so I think I'll only set this if I need it. Hope someone finds this helpful.