Bug 8839 - AMD cpu running at full speed with default 'performance' cpufreq governor
Summary: AMD cpu running at full speed with default 'performance' cpufreq governor
Status: RESOLVED DUPLICATE of bug 14584
Alias: None
Product: Mageia
Classification: Unclassified
Component: RPM Packages (show other bugs)
Version: Cauldron
Hardware: x86_64 Linux
Priority: Normal normal
Target Milestone: ---
Assignee: Thomas Backlund
QA Contact:
URL:
Whiteboard: INERRATA
Keywords:
Depends on:
Blocks:
 
Reported: 2013-01-27 13:26 CET by Asimov Solensan
Modified: 2015-05-15 14:28 CEST (History)
2 users (show)

See Also:
Source RPM: kernel
CVE:
Status comment:


Attachments

Description Asimov Solensan 2013-01-27 13:26:59 CET
Description of problem:

The module powernow_k8 is not loaded automatically. This means that the CPU runs at it's max speed all the time. Which isn't a good thing in a hardware menant to be used in laptops.

It has a huge impact on the battery life.

How reproducible:

Easiest way is to install powertop and in the frequency stats tab you can see clearly that the CPU only has a single mode.

Steps to Reproduce:
1.Just run powertop to verify available modes for the cpu
2.Load manually #modprobe powernow_k8
3.Run again powertop to see that now it supports several frequencies.

Additional details:

Although having the module loaded the CPU runs always at it's max speed because the cpufreq governor is set by default to "performance", on a laptop it should be set to "ondemand"
Manuel Hiebel 2013-01-27 14:00:44 CET

Component: Installer => RPM Packages
Assignee: bugsquad => tmb
Source RPM: (none) => kernel

Comment 1 Philippe Leblanc 2013-05-28 22:32:03 CEST
I just read somewhere that powernow_k8 has been deprecated in kernel since kernel 3.7. It has been replaced by acpi_cpufreqd. Please post the output of "cpupower frequency-info".

CC: (none) => philippe.l

Comment 2 Philippe Leblanc 2013-05-28 22:35:38 CEST
sorry that would be acpi_cpufreq without the "d".
Comment 3 Manuel Hiebel 2013-10-22 12:21:12 CEST
This message is a reminder that Mageia 2 is nearing its end of life.
Approximately one month from now Mageia will stop maintaining and issuing updates for Mageia 2. At that time this bug will be closed as WONTFIX (EOL) if it remains open with a Mageia 'version' of '2'.

Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Mageia version prior to Mageia 2's end of life.

Bug Reporter: Thank you for reporting this issue and we are sorry that we may not be able to fix it before Mageia 2 is end of life.  If you would still like to see this bug fixed and are able to reproduce it against a later version of Mageia, you are encouraged to click on "Version" and change it against that version of Mageia.

Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Mageia release includes newer upstream software that fixes bugs or makes them obsolete.

-- 
The Mageia Bugsquad
Comment 4 Manuel Hiebel 2013-11-23 16:16:40 CET
Mageia 2 changed to end-of-life (EOL) status on ''22 November''. Mageia 2 is no
longer maintained, which means that it will not receive any further security or
bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of Mageia
please feel free to click on "Version" change it against that version of Mageia
and reopen this bug.

Thank you for reporting this bug and we are sorry it could not be fixed.

--
The Mageia Bugsquad

Status: NEW => RESOLVED
Resolution: (none) => OLD

Comment 5 Florian Hubold 2015-05-15 11:59:52 CEST
Seems this issue still persists or came back. With acpi-cpufreq, and the default governor being set to ondemand, affected CPU is Phenom II 720 and it seems to have worked OK with mga3 and mga4. Check https://forums.mageia.org/en/viewtopic.php?f=7&t=9801

FWIW, the wiki article about cpupower that mentions powernow_k8 to be deprecated in favour of acpi-cpufreq is this one:
https://wiki.archlinux.org/index.php/CPU_frequency_scaling#CPU_frequency_driver
I wonder why we still have it as kernel module if it's deprecated?

Anyways, the CPU is running at full speed by default due to the performance governor, and that's a bad thing and a regression compared to mga4.

Status: RESOLVED => REOPENED
CC: (none) => doktor5000
Version: 2 => Cauldron
Resolution: OLD => (none)

Samuel Verschelde 2015-05-15 12:20:34 CEST

Whiteboard: (none) => MGA5TOO

Florian Hubold 2015-05-15 12:58:21 CEST

Summary: Powersaving module "powernow_k8" not loaded automatically on AMD E2 (brazos) => AMD cpu running at full speed with default 'performance' cpufreq governor

Comment 6 Florian Hubold 2015-05-15 14:28:03 CEST
(In reply to Florian Hubold from comment #5)
> Anyways, the CPU is running at full speed by default due to the performance
> governor, and that's a bad thing and a regression compared to mga4.

According to bug 13368 and bug 14584 this is expected and required for Intel CPU's, as those do only support performance or powersave, and cpufreq service will fail if something else is set. Hence performance is the default.

So we need an Errata entry for the default cpufreq governor being "performance" and AMD CPU users might need to switch that actively to "ondemand".
In effect similar to https://wiki.mageia.org/en/Mageia_2_Errata#Powersaving_features_not_enabled_by_default_on_AMD_E2_.28brazos.29_CPU.27s but slightly different wording.

Added https://wiki.mageia.org/en/Mageia_5_Errata#default_cpufreq_governor_is_performance.2C_some_.5BAMD.5D_users_might_need_to_switch_to_ondemand

*** This bug has been marked as a duplicate of bug 14584 ***

Status: REOPENED => RESOLVED
Resolution: (none) => DUPLICATE
Whiteboard: MGA5TOO => INERRATA


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