cpufreq broken on core2duo

[John Baldwin]

On Wednesday 04 June 2008 07:09:35 pm Evren Yurtesen wrote:
> Roland Smith wrote:
> > On Thu, Jun 05, 2008 at 08:33:24AM +1000, Andrew Snow wrote:
> >> Here's another one:
> >> CPU: Intel(R) Xeon(R) CPU  E5410  @ 2.33GHz
> >> cpu0: <ACPI CPU> on acpi0
> >> est0: <Enhanced SpeedStep Frequency Control> on cpu0
> >> est: CPU supports Enhanced Speedstep, but is not recognized.
> >> est: cpu_vendor GenuineIntel, msr 720072006000720
> >> device_attach: est0 attach returned 6
> >> p4tcc0: <CPU Frequency Thermal Control> on cpu0
> >  
> > I had this on a new core2 quad. Updating to a recent 7-STABLE fixed the
> > issue for me.
> 
> Did any of you tried chkfreq which comes with acpi_ppc 
> http://www.spa.is.uec.ac.jp/~nfukuda/software/ to check if the cpu frequency 
is 
> actually changing?

chkfreq checks the frequency by reading the TSC and comparing it across a 
sleep.  However, newer CPUs actually fix the TSC to increment at a constant 
rate (so at lower CPU speeds 1 CPU tick may actuall be N TSC ticks) to make 
it easier to use the TSC for timekeeping.  Thus, chkfreq will think that 
newer CPUs are running at the maximum speed when they aren't.  This is 
actually a feature of newer CPUs.

Try turning off powerd and using 'openssl speed rsa' at different frequencies 
to check for real frequency changes.

-- 
John Baldwin