From: Dirk Brandewie <dirk.brandewie@gmail.com>
To: "Jörg Otte" <jrg.otte@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
rafael.j.wysocki@intel.com
Subject: Re: [v3.10-rc] intel_pstate question
Date: Tue, 28 May 2013 08:52:46 -0700 [thread overview]
Message-ID: <51A4D2CE.90604@intel.com> (raw)
In-Reply-To: <CADDKRnDH130wn8nVaT4xmCuEEcsGyBcjhj7pDjPMkeucUW+EWw@mail.gmail.com>
Hi Jörg,
On 05/28/2013 08:02 AM, Jörg Otte wrote:
> Hi,
>
> the sysfs-interface of intel_pstate is different to that of the acpi driver:
> - intel_pstate shows current cpu-frequency in "cpuinfo_cur_freq" whereas
> the acpi counterpart uses "scaling_cur_freq".
> - moreover cpuinfo_cur_freq is readable by root only, whereas
> scaling_cur_freq is world readable.
>
> A monitoring tool must take care of theese differences.
> Is this intentional?
>
This is a side effect of the interface that intel_pstate presents to the cpufreq
core.
cpuinfo_cur_freq reports the value returned from the scaling driver.
scaling_cur_freq reports the current frequency in the governors policy structure.
intel_pstate has an internal governor so the core does not try to interpret
the policy structure.
I don't know why cpuinfo_cur_info is read-only root maybe Rafael knows the history.
> Thanks, Jörg
>
> Please CC me in answeres, I'm not subscribed.
>
next prev parent reply other threads:[~2013-05-28 15:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-28 15:02 [v3.10-rc] intel_pstate question Jörg Otte
2013-05-28 15:52 ` Dirk Brandewie [this message]
2013-05-29 9:25 ` Jörg Otte
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