Arch Linux

dslink

Member

From: USA

Registered: 2012-02-23

Posts: 48

CPU governor Arch Linux Vs Ubuntu

I wanted to try Steam out really fast and was having problems doing it with Arch, I switched over a blank drive and installed Ubuntu 15.10 I noticed that the CPU Freq moves up and down in Ubuntu. It doesn't just sit still at 1.60ghz set to "ondemand" like Arch does.
Now in Arch I do have the intel cpu microcode loaded but still the cpu never ever moves unless i set it to be performance manually. Why is this?  Why isn't it "adaptive" in Arch like it is in Ubuntu?

Ps this is an i7-3770

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,797

Re: CPU governor Arch Linux Vs Ubuntu

What kernel is Ubuntu running?  What kernel was Arch running?

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dslink

Member

From: USA

Registered: 2012-02-23

Posts: 48

Re: CPU governor Arch Linux Vs Ubuntu

Stock...

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: CPU governor Arch Linux Vs Ubuntu

just a guess, but maybe ubuntu is still using acpi-cpufreq for some reason..

Have you tried disabling intel_pstate on arch? https://wiki.archlinux.org/index.php/CP … ncy_driver

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,797

Re: CPU governor Arch Linux Vs Ubuntu

Stock...

That is the most perfectly useless answer I have ever seen.
Never mind. Good Luck

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almindor

Member

Registered: 2015-10-10

Posts: 33

Re: CPU governor Arch Linux Vs Ubuntu

Stock...

That is the most perfectly useless answer I have ever seen.
Never mind. Good Luck

It's not. Ubuntu 15.10 stock kernel version is known and so is Arch linux one. I don't see why this is an issue.

To be helpful here are the versions:

ubuntu 15.10: 4.2
Arch current: 4.2

You might argue that we don't know the exacts all the way down to compile options but then he probably wouldn't either. Unless ubuntu specifically uses a diff. driver or disabled the intel p-state the experience should be same.

Last edited by almindor (2015-11-05 16:24:25)

bstaletic

Member

Registered: 2014-02-02

Posts: 658

Re: CPU governor Arch Linux Vs Ubuntu

One can't expect experiance to be the same. Ubuntu is know for preconfiguring (and AFAIK patching) packages. More important than the actual versions of kernels are the configuration files for both. Also Arch doesn't have a default kernel and Ubuntu's can be upgraded.

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Arup

Member

From: Earth

Registered: 2014-02-20

Posts: 95

Re: CPU governor Arch Linux Vs Ubuntu

Both Arch and Ubuntu depend on kernel's stock pstate driver for Intel and for AMD its cpu-freq. My i7 Haswel and Skylake both vary as per cpufreq indicator in xfce Arch and Ubuntu unity.

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: CPU governor Arch Linux Vs Ubuntu

Haswell has a known upstream bug.  Search on my name and Haswell or wait for me to post a link for you when I am back home

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs

graysky

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From: :wq

Registered: 2008-12-01

Posts: 10,597

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Re: CPU governor Arch Linux Vs Ubuntu

https://bugzilla.kernel.org/show_bug.cgi?id=93521

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Arup

Member

From: Earth

Registered: 2014-02-20

Posts: 95

Re: CPU governor Arch Linux Vs Ubuntu

My 4790 i7 runs same temps in 14.04LTS and ARCH, the Ubuntu has latest 3.19 kernel. I will try out 15.10 next week and see if there is any difference. In XFCE Arch my CPUFREQ is shown nearabouts turbo when set to average mode readout.

fixide

Member

Registered: 2013-04-27

Posts: 44

Re: CPU governor Arch Linux Vs Ubuntu

Same issue here with my 4770k...

Lower freq : 3300. Never 800mhz. .

Arup

Member

From: Earth

Registered: 2014-02-20

Posts: 95

Re: CPU governor Arch Linux Vs Ubuntu

Same issue here with my 4770k...

Lower freq : 3300. Never 800mhz. .

Have you tried any other distro to see if this issue is Arch kernel specific?

fixide

Member

Registered: 2013-04-27

Posts: 44

Re: CPU governor Arch Linux Vs Ubuntu

No I have not tried with other distributions. I can try with a fedora livecd if you want.

On I7Z is clearly seen that the frequency is reduced very slightly and for a very short duration.

As against the C7 active well.

I believe the cpu can actually get down to 800 MHz but the kernel restarts something so it never stay down long.

I tested on my laptop (I5 old Arrandale) and it's fine for him on Arch. 1ghz @ idle

Last edited by fixide (2015-11-13 12:32:17)

Arup

Member

From: Earth

Registered: 2014-02-20

Posts: 95

Re: CPU governor Arch Linux Vs Ubuntu

Try Ubuntu and Fedora live to see if this issue is Arch specific. Currently even with light load or no load my 3.60GHz 4790 is always shown near about turbo frequency of 3.95+GHz or 4 GHz in average measurement mode.

graysky

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From: :wq

Registered: 2008-12-01

Posts: 10,597

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Re: CPU governor Arch Linux Vs Ubuntu

I saw improvements by tweaking the tickrate from 300 to 1000.  YMMV.  https://bbs.archlinux.org/viewtopic.php?id=193983

Last edited by graysky (2015-11-13 13:42:30)

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fixide

Member

Registered: 2013-04-27

Posts: 44

Re: CPU governor Arch Linux Vs Ubuntu

I come from a test with a fedora 23 livecd.

Verdict: the problem is Arch (or arch settings)

I am in idle between 800 and 1000 MHz on fedora on I7Z. On arch I do not drop below 3 GHz.

Last edited by fixide (2015-11-13 19:51:55)

Lone_Wolf

Forum Moderator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 11,928

Re: CPU governor Arch Linux Vs Ubuntu

fixide, which kernelversion is used by fedora 23 live ?

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fixide

Member

Registered: 2013-04-27

Posts: 44

Re: CPU governor Arch Linux Vs Ubuntu

On arch :
Linux Mithril 4.2.5-1-ARCH #1 SMP PREEMPT Tue Oct 27 08:13:28 CET 2015 x86_64 GNU/Linux

On fedora 23 live :

Note that i have C7 on arch but C1 on fedora.

Last edited by fixide (2015-11-13 20:48:54)

graysky

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From: :wq

Registered: 2008-12-01

Posts: 10,597

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Re: CPU governor Arch Linux Vs Ubuntu

@fixide - Post the output of the following under Arch and Fedora Live CD:

zgrep CONFIG_HZ /proc/config.gz | sed '/^#/d' && zgrep NO_HZ /proc/config.gz

Last edited by graysky (2015-11-13 21:25:19)

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fixide

Member

Registered: 2013-04-27

Posts: 44

Re: CPU governor Arch Linux Vs Ubuntu

On Fedora (with the good path for fedora)

zgrep CONFIG_HZ /boot/config-4.2.3-300.fc23.x86_64 | sed '/^#/d' && zgrep NO_HZ /boot/config-4.2.3-300.fc23.x86_64
CONFIG_HZ_1000=y
CONFIG_HZ=1000
CONFIG_NO_HZ_COMMON=y
# CONFIG_NO_HZ_IDLE is not set
CONFIG_NO_HZ_FULL=y
# CONFIG_NO_HZ_FULL_ALL is not set
# CONFIG_NO_HZ_FULL_SYSIDLE is not set
CONFIG_NO_HZ=y

With Arch :
zgrep CONFIG_HZ /proc/config.gz | sed '/^#/d' && zgrep NO_HZ /proc/config.gz
CONFIG_HZ_300=y
CONFIG_HZ=300
CONFIG_NO_HZ_COMMON=y
CONFIG_NO_HZ_IDLE=y
# CONFIG_NO_HZ_FULL is not set
# CONFIG_NO_HZ is not set

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

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Re: CPU governor Arch Linux Vs Ubuntu

@fixide - Yes, as I linked in my post, the tick rate difference was to blame on my hardware.  Experiment: build the linux package from ABS except change the tick rate from the Arch default of 300 to 1000.  Install that package and boot into it and repeat your measurements.  Before you reboot.  Get some data under the Arch default.  I provided a script to analyze the data you collect by running i7z.

https://bbs.archlinux.org/viewtopic.php … 3#p1506573

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fixide

Member

Registered: 2013-04-27

Posts: 44

Re: CPU governor Arch Linux Vs Ubuntu

it'll be the first time that I would use to customize a kernel with abs ... trying to find some tutos to change the tickrate... Meanwhile on my current kernel:
./stats.sh mylog.txt
median: 3647.84
count : 672

It is an arch bug?

ABSROOT=. abs core/linux
==> Starting ABS sync...
receiving file list ... done
...

Changed pkgbuild to pkgbase=linux-custom

Last edited by fixide (2015-11-13 22:08:19)

graysky

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From: :wq

Registered: 2008-12-01

Posts: 10,597

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Re: CPU governor Arch Linux Vs Ubuntu

Not too sure what you're doing...

sudo abs
cp -a /var/abs/core/linux .
cd linux
sed -i '/#make nconfig/ s,#,,' PKGBUILD
makepkg -srci

1) Update abs
2) Copy the linux dir to what you would like to build
3) Enter that dir
4) Uncomment the nconfig line so you can change the tickrate
5) Build the package and install it afterwards

Note that you will enter the nconfig and you can change the tick rate under:
Processor type and features
Timer frequency

Be sure you save the config before exiting (ESC twice and save there).

Last edited by graysky (2015-11-13 22:18:52)

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: CPU governor Arch Linux Vs Ubuntu

...be sure you test without browsers open.  Just idle in X.

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs