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?