Is AMD Turbo Core supported in DragonFly

Sepherosa Ziehau sepherosa at
Sun Jan 22 18:34:48 PST 2017

On Mon, Jan 23, 2017 at 10:06 AM,  <am_dxer at> wrote:
> Hello,
> I have Dragonfly running on a laptop with an AMD Richland processor that
> has a clock speed of 2.1 GHZ and a turbo of 2.9 GHZ. When I look at the
> stats in hw.acpi.cpu, I see that the highest choice available is 2100
> and the lowest is 1100.
> I was trying to determine if the 2100 speed associates with the top
> normal cpu speed of 2.1 GHZ or the 2.9 GHZ speed of turbo. Also, is
> there any way to verify if turbo core is correctly functioning on
> dragonfly? I found a bit of info related to Intel turbo boost and
> Dragonfly but couldn't find any prior discussions of turbo on AMD. From
> some information I found on Turbo Core and Linux, it appears that Turbo
> Core for the cpu is actually enabled through the Radeon driver so it
> would seem the radeon driver somehow plays a part in when the cpu boosts
> although I am just not sure. Thanks.

For the Intel CPUs, the p-state list will have an entry, whose
frequency is highest freq+1, e.g. for 2100Mhz, the freq is 2101.  That
entry is used to enable Turbo boost on Intel CPUs.  I'm not sure about
AMD CPUs though.  You can try loading aperf.ko, and run 'systat -sens
1', which will show you the real frequency that the CPUs are running


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