cpu won't stay in powersave mode

cpu won't stay in powersave mode

[Tom Bruno]

I'm in the process of writing an acpi daemon that will also take care of
cpufreq settings.

I have found that unless I set
/sys/device/system/cpu/cpu0/cpfreq/scaling_governer
  to powersave from the command line that /proc/cpuinfo will not change
and the speed will not stay at powersave speeds. 

With other programs like cpufreqd, using a cpu speed test posted on this
list, i have found that the cpu speed does indeed change even though
/proc/cpuinfo does not. 
 
However, i have found that after about 8-10 seconds the cpu test starts
reporting that the cpu is back to full speed even though the powersave
value is still in scaling_governer.

Like i said above if I change it via hand using echo, /proc/cpuinfo is
correct, and the cputest reports the correct speed constantly.

performance mode: 2.4ghz
powersave mode: 1.2ghz
Intel P4-M 2.4ghz
Dell Inspiron 8500 - Bios A05
kernel-2.6.0-test11


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Re: cpu won't stay in powersave mode

[Tom Bruno]

Sorry, accendtly hit reply instead of send to list.

On Mon, 2003-12-15 at 14:14, Thomas Renninger wrote:
> Tom Bruno wrote:
> 
> >Like i said above if I change it via hand using echo, /proc/cpuinfo
is
> >correct, and the cputest reports the correct speed constantly.
> >
> >performance mode: 2.4ghz
> >powersave mode: 1.2ghz
> >Intel P4-M 2.4ghz
> >Dell Inspiron 8500 - Bios A05
> >kernel-2.6.0-test11
> >  
> >
> /proc/cpu_info didn't work for me, too.
> However it seems to work now(after I changed the governors to be 
> compiled as modules(or the way around?)).
> 
I've now tried both as modules, and compiled in, /proc/cpuinfo works
niether report correctly.

> If you want to detemine the current real speed of your machine use the
> procspeed prog I posted some days ago(04.12, 09.12).

yes, that is the program i spoke of.  However, like i said, when
/proc/cpuinfo is reporting wrong, my system works it's way back to full
speed even though powersave is in the /sys scaling_governor.

It will report the changed speed (clockdown to 1.2ghz) for about 10
seconds, and then will start to report again at 2.4ghz even though the
setting haddn't changed.

-- 
Vwords.com Technology Services
 PC and Network Services for Southern Illinois
  Phone: 618-713-6896
-- 
Vwords.com Technology Services
 PC and Network Services for Southern Illinois
  Phone: 618-713-6896

Re: cpu won't stay in powersave mode

[Dominik Brodowski]

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On Mon, Dec 15, 2003 at 03:18:04PM +0000, Tom Bruno wrote:
> Sorry, accendtly hit reply instead of send to list.
> 
> On Mon, 2003-12-15 at 14:14, Thomas Renninger wrote:
> > Tom Bruno wrote:
> > 
> > >Like i said above if I change it via hand using echo, /proc/cpuinfo
> is
> > >correct, and the cputest reports the correct speed constantly.
> > >
> > >performance mode: 2.4ghz
> > >powersave mode: 1.2ghz
> > >Intel P4-M 2.4ghz
> > >Dell Inspiron 8500 - Bios A05
> > >kernel-2.6.0-test11
> > >  
> > >
> > /proc/cpu_info didn't work for me, too.
> > However it seems to work now(after I changed the governors to be 
> > compiled as modules(or the way around?)).
> > 
> I've now tried both as modules, and compiled in, /proc/cpuinfo works
> niether report correctly.
> 
> > If you want to detemine the current real speed of your machine use the
> > procspeed prog I posted some days ago(04.12, 09.12).
> 
> yes, that is the program i spoke of.  However, like i said, when
> /proc/cpuinfo is reporting wrong, my system works it's way back to full
> speed even though powersave is in the /sys scaling_governor.
> 
> It will report the changed speed (clockdown to 1.2ghz) for about 10
> seconds, and then will start to report again at 2.4ghz even though the
> setting haddn't changed.

I think the BIOS is meddling with the speedstep setting [this is more
common for older systems, but obviously some vendors still think it's a good
idea] . If it were cpufreq, the value in /proc/cpuinfo would be updated as
well.

Do you run an ACPI-enabled kernel? 

	Dominik

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Re: cpu won't stay in powersave mode

[Tom Bruno]

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On Fri, 2003-12-19 at 16:15, Dominik Brodowski wrote:
> On Mon, Dec 15, 2003 at 03:18:04PM +0000, Tom Bruno wrote:
> > Sorry, accendtly hit reply instead of send to list.
> > 
> > On Mon, 2003-12-15 at 14:14, Thomas Renninger wrote:
> > > Tom Bruno wrote:
> > > 
> > > >Like i said above if I change it via hand using echo, /proc/cpuinfo
> > is
> > > >correct, and the cputest reports the correct speed constantly.
> > > >
> > > >performance mode: 2.4ghz
> > > >powersave mode: 1.2ghz
> > > >Intel P4-M 2.4ghz
> > > >Dell Inspiron 8500 - Bios A05
> > > >kernel-2.6.0-test11
> > > >  
> > > >
> > > /proc/cpu_info didn't work for me, too.
> > > However it seems to work now(after I changed the governors to be 
> > > compiled as modules(or the way around?)).
> > > 
> > I've now tried both as modules, and compiled in, /proc/cpuinfo works
> > niether report correctly.
> > 
> > > If you want to detemine the current real speed of your machine use the
> > > procspeed prog I posted some days ago(04.12, 09.12).
> > 
> > yes, that is the program i spoke of.  However, like i said, when
> > /proc/cpuinfo is reporting wrong, my system works it's way back to full
> > speed even though powersave is in the /sys scaling_governor.
> > 
> > It will report the changed speed (clockdown to 1.2ghz) for about 10
> > seconds, and then will start to report again at 2.4ghz even though the
> > setting haddn't changed.
> 
> I think the BIOS is meddling with the speedstep setting [this is more
> common for older systems, but obviously some vendors still think it's a good
> idea] . If it were cpufreq, the value in /proc/cpuinfo would be updated as
> well.
> 
> Do you run an ACPI-enabled kernel? 
> 
> 	Dominik

  Yes, I have acpi enabled, and to the best of my knowledge, it is
functioning correclty, at least "externally"  /proc/acpi/events works
and returns events and stuff.  Don't know about non visiable internals
though.

New stats:
Dell Inspiron 8500
Bios: A05
Cpu:  Pentium-M 2.4ghz
Gentoo Linux
Kernel: 2.4.23, 2.6.0 


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