"new" (aus of 2.6.20) acpi_cpufreq and thinkpad z61m

"new" (aus of 2.6.20) acpi_cpufreq and thinkpad z61m

[Dietz Proepper]

Hi,

I've been playing around a lttle with a thikpad z61m (core 2 duo cpu,  945 
chipset) and acpi_cpufreq from 2.6.20-rc6 and found the follwoing strage 
behaviour:

Under "normal" circumstances, if I disconnect the ac power, the laptop 
pulls about 18W from the battery when idle (which nearly matchs idle 
consumption under Windows XP and is totally ok for the machine). 

But, every now and then, idle consumption goes up to about 25W, and goes 
down again only after a reboot (suspending to disk and resuming does not 
help). Needlessly to say that max/min frequencies are set to the right 
value and /sys/.../cpuinfo_cur_freq is at the min freq.

It seems that I can reproduce the above behaviour by setting the laptop 
under heavy load for some minutes (building a kernel seems to be 
sufficient).

Any idea?

thx alot,
	Dietz

Re: "new" (aus of 2.6.20) acpi_cpufreq and thinkpad z61m

[Thomas Renninger]

On Sun, 2007-02-04 at 11:57 +0100, Dietz Proepper wrote:
> Hi,
> 
> I've been playing around a lttle with a thikpad z61m (core 2 duo cpu,  945 
> chipset) and acpi_cpufreq from 2.6.20-rc6 and found the follwoing strage 
> behaviour:
> 
> Under "normal" circumstances, if I disconnect the ac power, the laptop 
> pulls about 18W from the battery when idle (which nearly matchs idle 
> consumption under Windows XP and is totally ok for the machine). 
> 
> But, every now and then, idle consumption goes up to about 25W, and goes 
> down again only after a reboot (suspending to disk and resuming does not 
> help). Needlessly to say that max/min frequencies are set to the right 
> value and /sys/.../cpuinfo_cur_freq is at the min freq.
It could also be the processor sleeping states:
cat /proc/acpi/processor/*/power

Try to unload drivers that could poll hardware and/or produce bus master
activity.
AFAIK this could be some wlan and USB modules and possibly others.

If you want to play a bit with power consumption:
latest -mm kernel should have dyntick patches in, which disables the
frequent
timer interrupt for a while in idle to be able to stay in deeper
sleeping states
for longer time. This should save you (if bus master activity stays low
and userspace
programs do not poll too much) a lot of battery life time.

    Thomas
> 
> It seems that I can reproduce the above behaviour by setting the laptop 
> under heavy load for some minutes (building a kernel seems to be 
> sufficient).
> 
> Any idea?
> 
> thx alot,
> 	Dietz
> 
> _______________________________________________
> Cpufreq mailing list
> Cpufreq@lists.linux.org.uk
> http://lists.linux.org.uk/mailman/listinfo/cpufreq

Re: "new" (aus of 2.6.20) acpi_cpufreq and thinkpad z61m

[Dietz Proepper]

Hi,

Thomas Renninger:
> On Sun, 2007-02-04 at 11:57 +0100, Dietz Proepper wrote:
> > Hi,
> >
> > I've been playing around a lttle with a thikpad z61m (core 2 duo cpu, 
> > 945 chipset) and acpi_cpufreq from 2.6.20-rc6 and found the follwoing
> > strage behaviour:
> >
> > Under "normal" circumstances, if I disconnect the ac power, the laptop
> > pulls about 18W from the battery when idle (which nearly matchs idle
> > consumption under Windows XP and is totally ok for the machine).
> >
> > But, every now and then, idle consumption goes up to about 25W, and
> > goes down again only after a reboot (suspending to disk and resuming
> > does not help). Needlessly to say that max/min frequencies are set to
> > the right value and /sys/.../cpuinfo_cur_freq is at the min freq.
>
> It could also be the processor sleeping states:
> cat /proc/acpi/processor/*/power

They look like they should, as far as I can see, also the state transition 
statistics.

> Try to unload drivers that could poll hardware and/or produce bus master
> activity.
> AFAIK this could be some wlan and USB modules and possibly others.

I see the behaviour even with no (apart from the cpufreq stuff) modules 
loaded and init=/bin/sh.

> If you want to play a bit with power consumption:
> latest -mm kernel should have dyntick patches in, which disables the
> frequent
> timer interrupt for a while in idle to be able to stay in deeper
> sleeping states
> for longer time. This should save you (if bus master activity stays low
> and userspace
> programs do not poll too much) a lot of battery life time.

For 2.6.20-final the beaviour changed a bit.  Now everything is fine, until 
I do a software suspend/resume (by means of swsusp2), then again the 
laptop hangs on high power consumption (and the cpus *are* in fact clocked 
down, run time of a little three liner that does some loops shows it 
clearly).

What leads me to the assumption that something in acpi-cpufreq might smell 
fishy is that if I use another driver (i.e. centrino-speedstep) I can not 
reproduce the above behaviour (reduction of power consumption is not as 
big as with acpi-cpufreq, but it works after a resume too ;-).

regards,
	Dietz