cpufreq & enhanced speedstep

Rui Paulo rpaulo at fnop.net
Tue May 15 00:09:03 UTC 2007

At Mon, 14 May 2007 23:48:07 +0200,
Harald Schmalzbauer wrote:
> Am Freitag, 24. Juni 2005 schrieb Colin Percival:
>                      ^^^^
> [...]
> > > est0: <Enhanced SpeedStep Frequency Control> on cpu0
> > > est: CPU supports Enhanced Speedstep, but is not recognized.
> > > est: Please update driver or contact the maintainer.
> > > est: cpu_vendor GenuineIntel, msr 6120d2606000d26, bus_clk, 64
> > > device_attach: est0 attach returned 6
> >
> > ... but I know exactly how est works, since I wrote it.  You have a
> > recent processor for which Intel hasn't released the frequency/voltage
> > tables; as a result, the est driver can't support it.
> >
> > (Apparently the data I need is in an NDA'ed BIOS writers' guide.  Can
> > anyone convince Intel to give me a copy?)
> Is this still valid?
> I have a E6600 core2 and tried to reduce power dissipation by enabling some 
> speedstep technology.
> acpi_perf seems to work since dev.cpu.freq shows 800 (possible 2400/1600/800) 
> and goes up while compiling, but I frequently get the following errors:
> kernel: acpi_perf0: Px transition to 1600 failed
> kernel: acpi_perf0: set freq failed, err 6

I don't really know why it fails..

> So I disabled acpi_perf and tried cpufreq with the following result:

In your machine acpi_perf gives the values to est. If you disable
acpi_perf, est will not work.

> I had acpi_perf and powerd enabled the last two days and the "feeling" of my 
> X11/KDE desktop was a bit bumpy; The mouse frequently hung for some 10s of 
> ms, in general the respnsiveness suffered a lot with dev.cpu.0.freq=800, a 
> lot more than 298 with est...

298 comes from p4tcc or acpi_throttle. These values usually reduce a
lot the CPU power to prevent thermal problems.

Maybe they should be separated...

> P.S.: disabling p4tcc (hint.p4tcc.0.disabled=1 in loader.conf when cpufreq is 
> loaded) hangs the machine at kickstart. In single user mode 'sysctl dev.cpu' 
> also hangs the machine.

Can you try:


Rui Paulo

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