From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andras.Horvath@cern.ch Subject: Re: Intel Clovertown vs. frequency scaling Date: Fri, 12 Oct 2007 17:01:26 +0200 Message-ID: <20071012150126.GY6058@cern.ch> References: <20071011150633.GL6058@cern.ch> <653FFBB4508B9042B5D43DC9E18836F5017D897B@scsmsx415.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <653FFBB4508B9042B5D43DC9E18836F5017D897B@scsmsx415.amr.corp.intel.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org+glkc-cpufreq=m.gmane.org@lists.linux.org.uk To: cpufreq@lists.linux.org.uk > With latest kernels (2.6.22 and beyond) you should use acpi-cpufreq and > not speedstep-centrino. ah, thanks. :-) I found that that too was compiled in (and in fact that's what's driving the Woodcrest box as well). > The frequencies supported depends on bus speed and voltages supported by > the CPU. I think the thing here is you have a low voltage part which is > already running at lowest possible voltage and does not support any more > frequency/voltage reduction. Hm. So there are no P* states available (always running at top speed) but the CPU just goes to some C* state when it's idle? This looks right (even if I find it strange) as the specs (http://download.intel.com/design/Xeon/datashts/31556903.pdf ) say that "Note: Not all Quad-Core Intel=AE Xeon=AE Processor 5300 Series are capable of supporting Enhanced Intel SpeedStep Technology. More details on which processor frequencies will support this feature will be provided in future releases of the Quad-Core Intel=AE Xeon=AE Processor 5300 Series NDA Specification Update when available." Nevertheless http://processorfinder.intel.com/details.aspx?sSpec=3DSLAEN says the L5335 has Enhanced Intel Speedstep support. > You mentioned that cpufreq works fine on Woodcrest, Intel L5160. > What are the freqs supported and what is the max freq for this part? As I said I was mistaken and it's using acpi-cpufreq. However, this: model name : Intel(R) Xeon(R) CPU 5160 @ 3.00GHz supports the following frequencies (2.6.23): # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies = 2997000 2664000 2331000 1998000 = Also, I have found myself another Clovertown: model name : Intel(R) Xeon(R) CPU E5345 @ 2.33GHz and this seems not to support no frequency scaling, no C-states, only thermal throttling. Can this be true? From the specs mentioned above I'd have expected at least some sort of halt state. http://processorfinder.intel.com/details.aspx?sSpec=3DSL9YL says 'enhanced intel speedstep' and C1E support, same as Mr. L5335 above. I'm getting more and more confused about this :) Andras