Enable per-core DVFS on Haswell

[MLiu24]

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.

[Ronny_G_Intel · Accepted solution]

Hi lmingcsce,

The following web forum may be useful, see here: https://software.intel.com/en-us/forums/watercooler-catchall/topic/497512 DVFS on Intel SandyBridge

Thanks,