Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965399Ab3E2JZN (ORCPT ); Wed, 29 May 2013 05:25:13 -0400 Received: from mail-oa0-f47.google.com ([209.85.219.47]:37202 "EHLO mail-oa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965344Ab3E2JZL convert rfc822-to-8bit (ORCPT ); Wed, 29 May 2013 05:25:11 -0400 MIME-Version: 1.0 In-Reply-To: <51A4D2CE.90604@intel.com> References: <51A4D2CE.90604@intel.com> Date: Wed, 29 May 2013 11:25:10 +0200 Message-ID: Subject: Re: [v3.10-rc] intel_pstate question From: =?UTF-8?Q?J=C3=B6rg_Otte?= To: Dirk Brandewie Cc: Linux Kernel Mailing List , rafael.j.wysocki@intel.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1623 Lines: 49 2013/5/28 Dirk Brandewie : > 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. > Thank you Dirk, for the information! Just another question: Now that processor 3a is supported, I am giving pstate driver a try on my notebook. This is the first time I see frequencies between above 2.5 and up to 3.1 GHz. With cpufreq driver I never saw that frequencies. So I think pstate driver uses turbo mode if appropriate (in contrast to cpufreq). is this correct? Thanks, Jörg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/