Read Base Clock Frequency

Read Base Clock Frequency

I understand that the frequency of the base clock varies between the nehalem and the sandy/ivy bridge architectures (133.33 MHz vs 100 MHz). Is there a way to read this number from an MSR or some other source? 

10 posts / 0 nouveau(x)
Dernière contribution
Reportez-vous à notre Notice d'optimisation pour plus d'informations sur les choix et l'optimisation des performances dans les produits logiciels Intel.
Portrait de Patrick Fay (Intel)

If there is another way, I have not seen it.

In my tools I have to check the cpuid family and model to see on which cpu I'm running and then use the appropriate 100 or 133 MHz speed.

Sorry,

Pat

>>...In my tools I have to check the cpuid family and model to see on which cpu I'm running and then use the appropriate 100 or
>>133 MHz speed.

Patrick, Could you be more specific, please?

Portrait de iliyapolak

IIRC I saw in the documentation that one of the MSR registers 0xCE reports base frequency.I need to check ISDM to verify this.

Portrait de Patrick Fay (Intel)

Hello Sergey,

It is just the standard, pain-in-the-rear code like:

if ( family == 0x6 && xmodel == 0x3e ) {

    bclock == 100 ;   // so cpu model is ivybridge, bclock is 100 MHz

} else if ( family == 0x6 && xmodel == 0x2a ) { // sandybridge...

the family and xmodel (extended model) is based on the CPUID app note http://www.intel.com/content/www/us/en/processors/processor-identification-cpuid-instruction-note.html

There is a discussion of using cpuid to ID cpu type at http://software.intel.com/en-us/articles/intel-architecture-and-processor-identification-with-cpuid-model-and-family-numbers

Pat

 

>>...the family and xmodel (extended model) is based on the CPUID app note...

Thanks for the note, Patrick. I didn't see processor-identification-cpuid-instruction-note.pdf document before.

Portrait de PONRAM

hope you may interested in the following link

software.intel.com/en-us/platform-monitoring

>>hope you may interested in the following link
>>
>>software.intel.com/en-us/platform-monitoring

Thanks for the link.

Great link PONRAM.

My conclusion for the original question is that Patrick's method using cpuid is the only viable option, and I have implemented that in my code. Thank you all for your responses.

Portrait de iliyapolak

Thank you PONRAM for the link.It contains a great amount of information.

Connectez-vous pour laisser un commentaire.