CPU speed not scaling properly (Fedora16)

basmoen · #1 11th February 2012, 08:03 PM

Hi!

Im a "regular" linuxuser who just migrated from M$,and love it!
I've been usin Fedora now and then for the last 6years,but now its permanent.

Just installed Fedora 16 on my laptop,and met a "small" problem.
The CPU scaling is totally wrong! It seems to be stuck @ 800MHz no matter what I do.

I've tried to figure out the "cpupower" commands,but Im still stuck,so now Im leaning on the community for help.

A little info that might help you figure out a solution for my problem:

From cpupower frequency-info:

Code:

# cpupower frequency-info
analyzing CPU 0:
  driver: powernow-k8
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 8.0 us.
  hardware limits: 800 MHz - 2.30 GHz
  available frequency steps: 2.30 GHz, 1.70 GHz, 800 MHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance
  current policy: frequency should be within 800 MHz and 800 MHz.
                  The governor "userspace" may decide which speed to use
                  within this range.
  current CPU frequency is 800 MHz (asserted by call to hardware).
  boost state support:
    Supported: no
    Active: no
    Boost States: 0
    Total States: 3
    Pstate-P0:  2300MHz
    Pstate-P1:  1700MHz
    Pstate-P2:  800MHz

When I installed Fedora,I chose the "laptop" install.

Just ask if you need more info

Thanks in advance!

dd_wizard · #2 11th February 2012, 08:37 PM

From reading "man cpupower-frequency-set", I'd say you should try:

Code:

sudo cpupower -c all frequency-set -g ondemand

I'm not sure how the governor got set to userspace, the default is normally ondemand.

dd_wizard

basmoen · #3 11th February 2012, 08:46 PM

Quote:

Originally Posted by dd_wizard

From reading "man cpupower-frequency-set", I'd say you should try:

Code:

sudo cpupower -c all frequency-set -g ondemand

I'm not sure how the governor got set to userspace, the default is normally ondemand.

dd_wizard

Thanks,but it still reports that it runs between 800MHz and 800MHz :P

Code:

current policy: frequency should be within 800 MHz and 800 MHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 800 MHz (asserted by call to hardware).

Is there some further information I can provide that might help?

PabloTwo · #4 11th February 2012, 09:33 PM

Looks like you also need to do:

Code:

cpupower set -c all frequency-set --min 800MHz --max 2.30GHz

RupertPupkin · #5 11th February 2012, 09:37 PM

Looks like you've run into the same bug that I did. See this thread: http://forums.fedoraforum.org/showthread.php?t=272109

Read through the comments and you'll see that there is a bugzilla report about this. In the meantime the only fix I found was to compile a custom kernel with cpu frequency scaling disabled.

basmoen · #6 11th February 2012, 10:03 PM

Quote:

Originally Posted by PabloTwo

Looks like you also need to do:

Code:

cpupower set -c all frequency-set --min 800MHz --max 2.30GHz

Still stuck

But thanks for the try

Quote:

Looks like you've run into the same bug that I did. See this thread: http://forums.fedoraforum.org/showthread.php?t=272109

Read through the comments and you'll see that there is a bugzilla report about this. In the meantime the only fix I found was to compile a custom kernel with cpu frequency scaling disabled.

Thanks! Ill give it a try. Im only using my laptop at home,so batterytime is not verry important for me.

RupertPupkin · #7 14th February 2012, 07:50 PM

It's possible that this bug may be fixed in the 3.2.6 kernel. The first item in the changelog here looks like it could be related, since the bad indexes give the wrong speeds. The 3.2.6 kernel is in the updates-testing repo, so it should be available soon in the updates repo. If you can't wait until then, you could do this:

Code:

yum --enablerepo=updates-testing update kernel

I would try it out myself but I'm actually happy now with compiling my own custom kernels, and I don't mind having my cpu running full speed all the time.

***DBelton*** · #8 15th February 2012, 01:12 AM

I was able to get mine to run at the full overclocked speed by disabling EIST (speedstep) in the BIOS. Cpufreq then loads P4-clockmod instead of the performance or ondemand governor.

If I didn't do that, it would only allow the maximum speed to be set to what the processor specs are, not the true overclocked speed.

I'm about ready to go the same route that Rupert did up there, and throw cpufreq where it belongs.. In the trash. I had decent results using cpuspeed, but cpufreq in the kernel is trash.

basmoen · #9 15th February 2012, 02:38 PM

@DBelton: I've been looking for somethink like that in my BIOS,but it seems that there is no support for that. Mabye I just have to update it. The BIOS is from 2010,so mabye it would help? Gonna look into that later anyways

@RupertPupkin: Thanks for the tip! I'll give it a try!

Anyways,right now im running a custom kernel. Just compiled a standard kernel without the CPU scaling. So now its running @2,3GHz all the time. Atleast its not slow anymore! 800MHz that I had earlier was a nightmare!

RupertPupkin · #10 15th February 2012, 06:28 PM

Well it was worth a try, but unfortunately kernel 3.2.6 didn't fix the problem for me:

Code:

# uname -morv
3.2.6-3.fc16.x86_64 #1 SMP Mon Feb 13 20:35:42 UTC 2012 x86_64 GNU/Linux
# cpupower frequency-info
analyzing CPU 0:
  driver: powernow-k8
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 1.24 ms.
  hardware limits: 1000 MHz - 2.20 GHz
  available frequency steps: 1000 MHz, 1.80 GHz, 2.00 GHz, 2.20 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance
  current policy: frequency should be within 1000 MHz and 1000 MHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz (asserted by call to hardware).
  boost state support:
    Supported: no
    Active: no

And running "cpupower -c all frequency-set --min 1000MHz --max 2.20GHz" as root had no effect.

So looks like I'm sticking with custom kernels.

basmoen · #11 15th February 2012, 07:33 PM

Quote:

Originally Posted by RupertPupkin

Well it was worth a try, but unfortunately kernel 3.2.6 didn't fix the problem for me:

Code:

# uname -morv
3.2.6-3.fc16.x86_64 #1 SMP Mon Feb 13 20:35:42 UTC 2012 x86_64 GNU/Linux
# cpupower frequency-info
analyzing CPU 0:
  driver: powernow-k8
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 1.24 ms.
  hardware limits: 1000 MHz - 2.20 GHz
  available frequency steps: 1000 MHz, 1.80 GHz, 2.00 GHz, 2.20 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance
  current policy: frequency should be within 1000 MHz and 1000 MHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz (asserted by call to hardware).
  boost state support:
    Supported: no
    Active: no

And running "cpupower -c all frequency-set --min 1000MHz --max 2.20GHz" as root had no effect.

So looks like I'm sticking with custom kernels.

Just the same here, but Im stuck at 800MHz,so Im sticking to my custom kernel too :/
Gonna buld a new and more stipped kernel in a few days tho. Right now my kernel has a ton of junk I dont need since i built a "stock" kernel,and only removed til CPU scaling.

Thanks for all help folks!

longhaven · #12 27th February 2012, 09:08 PM

Same problem with 3.2.7 kernel in my case:

# cpupower frequency-info analyzing CPU 0:
driver: powernow-k8
CPUs which run at the same hardware frequency: 0 1
CPUs which need to have their frequency coordinated by software: 0 1
maximum transition latency: 109 us.
hardware limits: 1000 MHz - 2.90 GHz
available frequency steps: 2.90 GHz, 2.80 GHz, 2.60 GHz, 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.80 GHz, 1000 MHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 1000 MHz and 2.90 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 1000 MHz (asserted by call to hardware).
boost state support:
Supported: no
Active: no

However, when I used following:

# echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

# cpupower frequency-info
analyzing CPU 0:
driver: powernow-k8
CPUs which run at the same hardware frequency: 0 1
CPUs which need to have their frequency coordinated by software: 0 1
maximum transition latency: 109 us.
hardware limits: 1000 MHz - 2.90 GHz
available frequency steps: 2.90 GHz, 2.80 GHz, 2.60 GHz, 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.80 GHz, 1000 MHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 1000 MHz and 2.90 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 2.90 GHz (asserted by call to hardware).
boost state support:
Supported: no
Active: no

It seems I can change the minimum scaling value to one of the valid steps and switch back to the ondemand governor and the new speed will be the new minimum I set with the appropriate echo command. Seems I saw something regarding a boot parameter re: acpi that had to be set for powernow-k8 to work properly, but can't find it right now. I'm also not sure if this approach works across reboots. Could it be involved with change to systemd?

---------- Post added at 04:08 PM ---------- Previous post was at 11:51 AM ----------

Must apologize: Powernow-k8 ondemand governor seems to be working just fine in kernel 3.2.7-1, at least for me.

marko · #13 27th February 2012, 09:28 PM

Quote:

Originally Posted by basmoen

Just the same here, but Im stuck at 800MHz,so Im sticking to my custom kernel too :/
Gonna buld a new and more stipped kernel in a few days tho. Right now my kernel has a ton of junk I dont need since i built a "stock" kernel,and only removed til CPU scaling.

Thanks for all help folks!

Don't just take cpupower command's word that the min and max freqs are the same, try to run something like a compile that should increase the clock, then look in the /proc/cpuinfo file to see if the quoted clock speed increased.

RupertPupkin · #14 31st May 2012, 07:04 PM

Looks like this bug has been fixed (at least for my cpu) with the 3.3.7-1 kernel in F17:

Code:

$ cpupower frequency-info
analyzing CPU 0:
  driver: powernow-k8
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 1.24 ms.
  hardware limits: 1000 MHz - 2.20 GHz
  available frequency steps: 1000 MHz, 1.80 GHz, 2.00 GHz, 2.20 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance
  current policy: frequency should be within 1000 MHz and 2.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz.
  boost state support:
    Supported: no
    Active: no

Looking at /proc/cpuinfo while running some cpu-intensive code confirmed that it does indeed reach 2.2GHz now, which agrees with that code running about twice as fast as under previous Fedora kernels. Yay!

cranil7 · #15 17th June 2012, 08:44 AM

RupertPupkin , I also have this problem. I am on fedora 17-64 bit.
I dont want to go "building custom Kernel" way. (To me building custom kernel is so difficult. I have back ground of hp unix administration and every damn module is easy to be marked for use or not. Linux is altogether different.)

I have few questions.
1. how do you see what kernel driver/in-built module is used for cpu frequency scaling?
(what are the ways to figure this out.)
2. as per 3.4 kernel, it seems you can pass on an option to kernel to load certain module or not. Not sure how to do it. do you know?
3. Can just exclude that driver while building dracut image?