You want Power Management (HWP/Speed Shift) on your Skylake to work?
Then please download/run debugMachKernel.sh after that you should boot with the -cpuid msgbuf=309212 arguments and enter the following command in a terminal window:
cat /var/log/system.log | grep 'cpuid_fn(0x00000006) eax:'
The result that I get here with a Intel i7-6700 is this:
cpuid_fn(0x00000006) eax:0x000007f7 ebx:0x00000002 ecx:0x00000009 edx:0x00000000
If CPUID.06H:EAX[bit 7] is set, then HWP provides several new architectural MSR’s: IA32_PM_ENABLE, IA32_HWP_CAPABILITIES, IA32_HWP_REQUEST and IA32_HWP_STATUS.
If CPUID.06H:EAX[bit 8] is set, then HWP provides IA32_HWP_INTERRUPT MSR to enable interrupt generation due to dynamic Performance changes and excursions.
If CPUID.06H:EAX[bit 9] is set, then HWP allows software to program the activity window in the IA32_HWP_REQUEST MSR.
If CPUID.06H:EAX[bit 10] is set, then HWP allows software to set an energy/performance preference hint in the IA32_HWP_REQUEST MSR. For the yet to be released MacBook9,1 this is set to 146. The default is 128.
If CPUID.06H:EAX[bit 11] is set, then HWP provides the IA32_HWP_REQUEST_PKG MSR to convey OS Power Management’s control hints for all logical processors in the physical package.
If CPUID.06H:EAX[bit 13] is set, then Hardware Duty Cycling is supported and the HDC base registers IA32_PKG_HDC_CTL, IA32_PM_CTL1, IA32_THREAD_STALL MSRs are supported. The primary use of HDC is to enable system software to manage low active workloads, to increase the package level C6 residency. Additionally, HDC can lower the effective average frequency in case or power or thermal limitation.
Edit: Here is the output of a next version of AppleIntelInfo.kext
One thing people definitely will have to get used to is the fact that the Most Efficient Performance is dynamically adjusted, and so far I have seen 1200, 1400, 1500 and 1600 MHz, yet CPUFloor is set to 800 MHz. And so is LFM.
And when I change the Energy Performance Preference to a lower or higher value, then I can immediately see the effect of it in the Intel Power Gadget.
Let me know what value you get. Thanks!