freq. scaling vs power consumption

[Billinghurst, David (RTATECH)]

> From: michalwd1979
 
> Hi,
> I wanted to tell about some strange results that I got yesterday. I
had an
> opportunity to accurate measure the power that my 2850 uses and the
> results are not as expected. I have 2x 3GHz XEON cpus, 4GB ram, 3xHDD.
I
> compiled my kernel with p4-clockmod freq. driver and
> /sys/devices/system/cpu/... shows that scaling is working. Max freq.
> 3000MHz min freq. 375MHz. The system is considerably slower with
lowest
> frequency, so I assume that processors speed really change. However
power
> used by the server does NOT change! I can see the difference with
no-load
> vs full-load (about 70W), but not with 3000 vs 375MHz. Does anybody
have
> any idea why? In that way using any frequency scaling (on this
machine) is
> not useful at all.


I posted similar results for a 1950 in April.

http://lists.us.dell.com/pipermail/linux-poweredge/2007-April/030629.htm
l


	David


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