How/why would dev.cpu.0.freq_levels change??!?

[Kevin Oberman]

> From: John Baldwin <jhb at freebsd.org>
> Date: Sat, 28 Jun 2008 17:38:40 -0400
> Sender: owner-freebsd-acpi at freebsd.org
> 
> On Friday 27 June 2008 07:53:19 pm David Wolfskill wrote:
> > My laptop is a Dell Inspiron 8200; I (ab)use it moderately heavily:
> > this includes tracking RELENG_6, RELENG_7, & HEAD on it, daily.
> > 
> > Lately there have been some times when "make buildworld" for RELENG_6
> > has taken a lot longer than it used to ... and I noticed that the
> > fans were on, even though it was running fairly cool (around 50C;
> > during a "make buildworld, around 85C is more common) -- and that
> > the machine was typically "topping out" at half speed (1200 MHz).
> > 
> > During these times, querying dev.cpu.0.freq_levels would yield a list
> > that did, ini fact, max out at 1200 MHz, when I know that it has gone up
> > to 2400 MHz in the past.
> > 
> > When it does this, the only circumvention I've been able to find is a
> > power-cycle.  Since I like to minimize disruption, this is annoying.
> > 
> > This afternoon, it showed evidence of doing this stunt again, so I
> > carefully logged out, powered the machine off, waited about 5 minutes,
> > then powered it back on.
> > 
> > But this time, I decided to fire up a little loop to display a timestamp
> > and the ooutput from "sysctl -n hw.acpi.thermal.tz0.temperature
> > dev.cpu.0.freq dev.cpu.0.freq_levels" every 5 seconds.
> > 
> > Here's the interval in question:
> > 
> > 1214609737,60.5C,300,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 
> 600/0 450/0 300/0 150/0
> > 1214609742,59.5C,450,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 
> 600/0 450/0 300/0 150/0
> > 1214609748,59.5C,450,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 
> 600/0 450/0 300/0 150/0
> > 1214609752,57.5C,150,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 
> 600/0 450/0 300/0 150/0
> > 1214609757,57.5C,600,1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0
> > 1214609762,56.5C,150,1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0
> > 1214609767,56.5C,150,1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0
> 
> Looks like it lowered the temperature.  Your BIOS might have decided to change 
> the levels to force the CPU to throttle down to cool the system.

Any chance you moved to battery at any time? My ThinkPad BIOS drops my
CPU's top speed from 2G to 800M when I go onto battery.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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