Re: Enforce _PPC limits

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

Hi Linda,

On Tue, 2016-05-24 at 16:37 -0400, Linda Knippers wrote:
> Hi Srinivas,
> 
> I have a couple of questions about this patch set.
> http://comments.gmane.org/gmane.linux.power-management.general/75263
> 
> Sorry I'm a bit late to the party but I've just booted 4.6 on my
> system
> and noticed some things.
> 
> My first question is about enabling the feature by default on
> enterprise
> and performance servers.  Is there any way to disable it on these
> servers?
> I didn't see a way.  I'm always nervous when something starts looking
> at
> a table that perhaps wasn't used before or introduces a new behavior
> that
> might be unexpected.  Having a way out or not making it the default
> for a
> while would be nice.
If you were using acpi-cpufreq ever , this would have been active
anyway.
This was requested by some server vendors to turn on by default as they
want to be able to use node manager to control and don't want to have
any kernel command line addition.

Don't you want to be able to use _PPC to control. If you don't use _PPC
then this will not be effective.
You can turn off from kernel command line processor.ignore_ppc=1

> 
> My second question is about the 48 instances I got of this when I
> booted my
> 2 socket, 48-CPU box:
> 
> > intel_pstate: _PPC limits will be enforced
> I suppose in theory I could have limits for some CPUs and not others
> but
> even in that case, the message isn't helpful.  I think it should be
> made
> useful or go away, or at least only be printed once.
> 
Agree, I will downgrade the message to pr_debug.

Thanks,
Srinivas
> 
> Thanks,
> 
> -- ljk
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