Verify the frequency of a core

[pradeep hettiarachchi]

Hi,

Here what I did:
I set the "performance" governor for one of the cores and "ondemand"
governor on an another core. Then I noticed that the cores have
different frequencies.
Based of the above observation on different processors, I have a
couple of questions.

1) When I tried to frequency-scale in a core i7 processor, it allows
me to set different governors for individual cores. As per to my
understanding, the processor has 4 physical cores and 2 hardware
threads per core. (totaling 8 cores altogether)  This means, I should
not be able to set different frequencies in two adjacent cores (say
core 0 and core 1) as they both same hardware. My understanding is I
should not be able to set the individual core frequencies as explained
above.

2) When I played with Q6600 processor, I found that trough the
governor, I can set the individual core-frequency. But as per to the
literature, Intel does not provide a facility to frequency-scale in
individual cores but the frequency in the entire processor.

3) What does the governor do? Does it set the frequency of the core directly ?

4) Is there any way that I can verify the actual frequency of a core
other than the interface of the governor.  Do you recommend to use MSR
direly to change and  measure the frequency  of the system ?




Sincerely,

Pradeep M. Hettiarachchi