1 Reply Latest reply on Sep 8, 2015 3:48 PM by rguevara

    Enable per-core DVFS on Haswell

    lmingcsce

      Hi,

       

      Do you know how to enable per-core DVFS on a Haswell processor?


      My testbed is Intel i7-4720HQ processor. The OS is Ubuntu 14.04 and the driver is acpi-cpufreq. Using the cpufreq-set tool, I can set different

      frequency to individual core. Then I use cpufreq-info to check and it shows different CPUs run at different frequency.

       

      However, when I use cpufeq-aperf which directly reads from the msr register,  I found all CPUs actually run at the same frequency. The cpufreq-set tool

      actually changes the frequency of all CPUs. I also use two applications to verify this.

       

      As the white paper of Haswell has showed it supports per-core DVFS, do you know how to enable it on Ubuntu? Or do I miss something here?

       

      Thanks.