22.04 Intel Turboboost Issue

[fournogo]

Thought I would post this here first instead of hardware since I am new.

I installed Ubuntu 22.04 LTS on a system with an Intel i3-6100 cpu without turboboost. Recently, I swapped that cpu for an i7-6700 WITH turboboost. I updated the system BIOS and enabled turboboost within the bios. When I checked the intel-pstate flag for noturbo_boost, it said turboboost was disabled and I didn’t have permission to change it. I tried booting a few times with and without turboboost enabled in the BIOS with no luck. Next (to avoid doing a reinstall) I created a bootable flash drive from another PC with Ubuntu 22.04 LTS and booted into it. Same issue, no turboboost and no permission to enable it.

Finally, I formatted the flash drive and changed the ISO file to Ubuntu 18.04 and booted into it. This time, no issue getting turboboost to work. It let me change the pstate flag and started working immediately.

Is this likely a bug? Or just an incompatibility? The PC is from 2016 so seems a bit soon for it to start doing this.

Or, is there something that might be persistent from the installation of 22.04 on my system and on the flash drive? Would reinstalling the OS entirely help? I’d like to avoid it if possible but am willing to if needed.

[DuckHook]

Welcome to the forums, fournogo.

You may very well have detected a regression in Jammy. These things do happen: a fix is made in a prior version that gets dropped in the more recent one.

I hope that others who are more knowledgeable in kernel matters will chime in here, but, to me, it doesn't make sense to reinstall. If a LiveUSB of Jammy doesn't turn this flag on, then neither will a reinstall.

However, one thing does occur to me: perhaps the newer kernel no longer requires turboboost and enhances performance some other way. The way to test that is to stress test your cpu under Bionic (with turboboost on) and then compare it to Jammy, where turboboost is unavailable. If the benchmarks are similar, then that means you are getting boosted performance anyway.

[MAFoElffen]

For Ubuntu 22.04.x, Use this kernel boot parameter and see if it helps:

intel_idle.max_cstate=4

[Doug S]

Which kernel versions are you using? What method are you using to check the flag, primitive commands or some utility? Please show us your commands and results.

I only use primitives. Example:

doug@s19:~/c$ grep . /sys/devices/system/cpu/intel_pstate/no_turbo
0
doug@s19:~/c$ echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
[sudo] password for doug:
1
doug@s19:~/c$ grep . /sys/devices/system/cpu/intel_pstate/no_turbo
1
doug@s19:~/c$ echo 0 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
0
doug@s19:~/c$ grep . /sys/devices/system/cpu/intel_pstate/no_turbo
0
doug@s19:~/c$

Are you sure your system is using the intel_pstate CPU frequency scaling driver?

doug@s19:~/c$ grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu10/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu11/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu1/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu2/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu3/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu4/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu5/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu6/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu7/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu8/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu9/cpufreq/scaling_driver:intel_pstate

[MAFoElffen]

Aren't you rather wanting expand that to look at

mafoelffen@Mikes-B460M:~$ grep . /sys/devices/system/cpu/intel_pstate/*
/sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost:0
/sys/devices/system/cpu/intel_pstate/max_perf_pct:100
/sys/devices/system/cpu/intel_pstate/min_perf_pct:15
/sys/devices/system/cpu/intel_pstate/no_turbo:0
/sys/devices/system/cpu/intel_pstate/num_pstates:45
/sys/devices/system/cpu/intel_pstate/status:active
/sys/devices/system/cpu/intel_pstate/turbo_pct:54
mafoelffen@Mikes-B460M:~$ sudo dmidecode | grep 'Max Speed\|Maximum Capacity'
    Maximum Capacity: 64 GB
    Max Speed: 8300 MHz
mafoelffen@Mikes-B460M:~$ grep . /sys/devices/system/cpu/cpu0/cpufreq/*
/sys/devices/system/cpu/cpu0/cpufreq/affected_cpus:0
/sys/devices/system/cpu/cpu0/cpufreq/base_frequency:2800000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq:5200000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency:0
/sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_preferences:default performance balance_performance balance_power power 
/sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference:balance_performance
/sys/devices/system/cpu/cpu0/cpufreq/related_cpus:0
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors:performance powersave
/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq:800176
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:powersave
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq:5200000
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed:<unsupported>

https://bugs.debian.org/cgi-bin/bugr...cgi?bug=981807

I think I found the root cause. My CPU model is Intel(R) Core(TM) i5-10210U CPU @ 1.60GHz. On linux 5.9 the max c-state it can enter is C6 but after 5.10 it'll happily go to C8. After entering deep c-state all sort of weird memory corruption and lockup starts to show up. Testing with boot parameter intel_idle.max_cstate=4 it seems the system becomes stable again and c-state is capped at C6. C7 is also not safe.

User's have reported that this boot parameter has also helped them with recent Intel TurboBoost problems that are similar to the OP's...

[Doug S]

Aren't you rather wanting expand that to look at

Okay, sure. I was keeping it simple, for now.

User's have reported that this boot parameter has also helped them with recent Intel TurboBoost problems that are similar to the OP's...

I was not aware of this, do not understand, and would like to know more.

[DuckHook]

User's have reported that this boot parameter has also helped them with recent Intel TurboBoost problems that are similar to the OP's...

I had no idea what "c-states" and the related technology was until this thread motivated me to learn. You guys teach me interesting new things about the guts of Linux all the time. Cool stuff.

I was not aware of this, do not understand, and would like to know more.

I don't know if you are asking about the deep technical aspects of this particular problem, but here's an overview that I found useful: https://www.golinuxhub.com/2018/06/w...pu-core-linux/

Now that know something about this, the tinkerer side of me is trying to talk me into fooling around with it, while my sensible side is telling me to refrain from fixing what ain't broken.

[MAFoElffen]

On answers from AskUbuntu for Ubuntu 18.04, I see your answer:
https://askubuntu.com/questions/1077...properly-18-04
https://askubuntu.com/questions/3761.../991839#991839
(I really like his script for setting CPU frequencies...)

But on Reddit and the GitHub for PopOS I see that parameter...
https://www.reddit.com/r/Ubuntu/comm...se_turboboost/
https://www.reddit.com/r/pop_os/comm...te4_for_every/
https://github.com/pop-os/linux/issu...ment-820920728

According to this table here: (from https://www.golinuxhub.com/2018/06/w...pu-core-linux/)

You would think that setting it to "0" would give it the most voltage and least restrictions, but the reports from other users (from Reddit and PopOS) say that somehow setting the max limit to 4 to limit it from going any further that cstate 4 helps them...

This was a good read for c-states in Linux: https://wiki.bu.ost.ch/infoportal/_m....1_nov2013.pdf

[Doug S]

Thanks for the references and info. I am very familiar with idle and the various governors and such. I was not familiar with any correlation between limiting idle states and turboboost functionality (and still don't see it). Sorry for any confusion.

By the way, there is a high energy cost for limiting to idle state 0 or "poll" (one reference mentioned using "poll"). Example, very idle system:

1.) Normal, all idle states enabled:

doug@s19:~$ sudo turbostat --quiet --Summary --show Busy%,Bzy_MHz,IRQ,PkgWatt,PkgTmp,RAMWatt,GFXWatt,CorWatt --interval 15
Busy%   Bzy_MHz IRQ     PkgTmp  PkgWatt CorWatt GFXWatt RAMWatt
0.07    3673    1192    33      1.42    0.77    0.00    0.89
0.06    3878    921     33      1.42    0.76    0.00    0.89

2.) All idle states deeper than 0 disabled:

doug@s19:~/idle$ sudo turbostat --quiet --Summary --show Busy%,Bzy_MHz,IRQ,PkgWatt,PkgTmp,RAMWatt,GFXWatt,CorWatt --interval 15
Busy%   Bzy_MHz IRQ     PkgTmp  PkgWatt CorWatt GFXWatt RAMWatt
99.76   4800    180754  67      53.88   53.22   0.00    0.89
99.76   4800    180307  67      53.66   53.00   0.00    0.89
99.76   4800    180784  68      53.63   52.97   0.00    0.89
doug@s19:~/idle$ grep . /sys/devices/system/cpu/cpu5/cpuidle/state*/disable
/sys/devices/system/cpu/cpu5/cpuidle/state0/disable:0
/sys/devices/system/cpu/cpu5/cpuidle/state1/disable:1
/sys/devices/system/cpu/cpu5/cpuidle/state2/disable:1
/sys/devices/system/cpu/cpu5/cpuidle/state3/disable:1

Note: Only CPU 5 was shown for briefity.

[MAFoElffen]

Thanks for the references and info. I am very familiar with idle and the various governors and such. I was not familiar with any correlation between limiting idle states and turboboost functionality (and still don't see it). Sorry for any confusion.

I come from both Linux and Windows...

On Tom's Hardware, the common responses, when asked about Turboboost problems, the first things asked the OP is about the User's 'Power Plan'

Make sure windows power settings in control panel is set to either balanced or performance. If it's on power saving or something else change it then restart the computer and see if it goes up to the turbo speeds.

(...then this explanation)

Turboboost is dependent on workload, temperatures, & number of active cores. With more cores active the less boost you get, usually dropping to none at all cores active.

Also almost always asked is if it is a Laptop, if a Laptop, if it is plugged in... and if a desktop, what wattage PSU they are using. To ensure it has the power available to let it go into TurboBoost. Of course that all is dependent if the CPU has TurboBoost technology. LOL

max_cstate limits the powerstate from limiting voltages below a certain threshold right? Seems to help with recovering from sleep states, hibernation's, and being able to go into TurboBoost states.

Seems (from all concerned) that TurboBoots is heavily dependent on the power available to the CPU, along with many other factors. (not just one switch)

I respect your knowledge of testing Kernels for Ubuntu and such. Just saying that there is more involved.