From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759969Ab3BOJrO (ORCPT ); Fri, 15 Feb 2013 04:47:14 -0500 Received: from mga09.intel.com ([134.134.136.24]:10534 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755253Ab3BOJrL convert rfc822-to-8bit (ORCPT ); Fri, 15 Feb 2013 04:47:11 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,672,1355126400"; d="scan'208";a="286172076" From: "Zhang, Rui" To: Andreas Mohr , "linux-kernel@vger.kernel.org" CC: "R, Durgadoss" , "peter@piie.net" , "lenb@kernel.org" Subject: RE: thermal governor: does it actually work?? Thread-Topic: thermal governor: does it actually work?? Thread-Index: AQHOCsiS9m4z/gHQmUWPsLihfR+t2Zh6pmhw Date: Fri, 15 Feb 2013 09:47:07 +0000 Message-ID: <744357E9AAD1214791ACBA4B0B90926329ED72@SHSMSX101.ccr.corp.intel.com> References: <20130214153255.GA5033@rhlx01.hs-esslingen.de> In-Reply-To: <20130214153255.GA5033@rhlx01.hs-esslingen.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Andreas Mohr [mailto:andi@lisas.de] > Sent: Thursday, February 14, 2013 11:33 PM > To: linux-kernel@vger.kernel.org > Cc: R, Durgadoss; Zhang, Rui; peter@piie.net > Subject: thermal governor: does it actually work?? > Importance: High > > For me after having loaded acerhdf the fan never stops (with kernelmode > active), despite staying safely below trip point > (acerhdf_set_cur_state() actually never gets called). Please attach the output of "grep . /sys/class/thermal/thermal_zone*/cdev*/*"? > And AFAIR in a 3.2.0 kernel acerhdf fan operation seemed to just work > (i.e., no fan for low temps, from the beginning). > Needless to say 3.2.0 didn't even feature all the modern thermal > governor crapyard yet ;) (ok, well, it's more complex but it's also a > very nice environment capability) > > 3.8-rc7: > CONFIG_ACPI_THERMAL=m > CONFIG_THERMAL=m > CONFIG_THERMAL_HWMON=y > CONFIG_THERMAL_DEFAULT_GOV_STEP_WISE=y > # CONFIG_THERMAL_DEFAULT_GOV_FAIR_SHARE is not set # > CONFIG_THERMAL_DEFAULT_GOV_USER_SPACE is not set CONFIG_FAIR_SHARE=y > CONFIG_STEP_WISE=y # CONFIG_USER_SPACE is not set # CONFIG_CPU_THERMAL > is not set > > > > Terminology in this area seems to be quite a bit off, too, at several > docs places, at least according to my understanding: > > e.g. drivers/thermal/step_wise.c has the following comment: > > /** > * step_wise_throttle - throttles devices associated with the given > zone > * @tz - thermal_zone_device > * @trip - the trip point > * @trip_type - type of the trip point > * > * Throttling Logic: This uses the trend of the thermal zone to > * throttle. > * If the thermal zone is 'heating up' this throttles all the cooling > * devices associated with the zone and its particular trip point, by > * one > * step. If the zone is 'cooling down' it brings back the performance > of > * the devices by one step. > > > > if ... heating up ... throttles ... > Sorry, but at least for P4 clockmod stuff (or some such), throttle > states (P1...P8 IIRC) meant that the CPU operation was *reduced*, i.e. > with pause intervals. For processors, surely you are right. > And the translation of throttle clearly says that it does go that way > and not the other way... > (yes, you managed to confuse me that much that I even had to look up > things to verify) > The question is that if we can also call it "throttle" when reducing the device performance to generate less heat. I do not have a clear answer for this as I'm not a native English speaker. And what you're saying here may be right. Surely I can generate a patch to rename it if throttle can't be used in that way. Len, What's your idea on this? Thanks, rui > ... cooling down ... brings back ... > This should certainly be worded "reduces" or some such. > > So, any idea why I'm missing callbacks in acerhdf (if that is what I'm > supposed to expect to happen)? > Kernel bug, .config mistake, missing/wrong user-side setup? > > Needless to say if kernel bug this ought to be fixed pre-3.8 ideally. > > Thanks, > > Andreas Mohr