Re: [Xen-devel] [PATCH 1/2] cpufreq, powernow: enable/disable core performance boost for all cpus in policy

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.06.13 at 01:07, Jacob Shin <jacob.shin@xxxxxxx> wrote:
> On Wed, Jun 19, 2013 at 03:14:46PM -0500, Jacob Shin wrote:
>> Currently, enable/disable turbo mode on AMD is broken:
>> 
>> $ xenpm enable-turbo-mode 0 <-- works and proper CPU MSR bit is set
>> $ xenpm enable-turbo-mode 1 <-- silently broken, MSR bit not set
>> 
>> Since ->turbo is per policy, when user requests to enable/disable
>> turbo mode, we need to set the bit in all of the ->cpus that this
>> policy affects.
> 
> Sorry, I'll have to re-do this [PATCH 1/2], as it does not solve the
> problem on platforms with a separate policy per CPU.

But isn't a separate policy per CPU meaning that indeed you want
to only fiddle with the one CPU that the policy is getting changed
for?

> 1. We'll have to either globally enable/disable boost for all CPUs, or

That's clearly not a good path, as the interface is specifically
intending to allow per-policy control.

> 2. [if there is a easy way to do so] find all Node siblings and set
> their bits and policy->turbo as well.

That would be the way to go, pending clarification on the above.

Jan


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