Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756470Ab2BGA0n (ORCPT ); Mon, 6 Feb 2012 19:26:43 -0500 Received: from out5-smtp.messagingengine.com ([66.111.4.29]:37437 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756384Ab2BGA0e (ORCPT ); Mon, 6 Feb 2012 19:26:34 -0500 X-Sasl-enc: oQxI7fPAWc1B4PmIAwSFZrBo5DbZ3g5vn6/9o9RujrAn 1328574393 Date: Mon, 6 Feb 2012 16:18:18 -0800 From: Greg KH To: Amit Kachhap Cc: Pavel Machek , linux-pm@lists.linux-foundation.org, linaro-dev@lists.linaro.org, patches@linaro.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, rob.lee@linaro.org Subject: Re: [linux-pm] [RFC PATCH] thermal: Add support to report cooling statistics achieved by cooling devices Message-ID: <20120207001818.GB30840@kroah.com> References: <1326878467-17766-1-git-send-email-amit.kachhap@linaro.org> <20120206165658.GA28687@atrey.karlin.mff.cuni.cz> <20120206170348.GA19749@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2078 Lines: 53 On Mon, Feb 06, 2012 at 03:16:17PM -0800, Amit Kachhap wrote: > On 6 February 2012 09:03, Greg KH wrote: > > On Mon, Feb 06, 2012 at 05:56:58PM +0100, Pavel Machek wrote: > >> Hi! > >> > >> > Add a sysfs node code to report effective cooling of all cooling devices > >> > attached to each trip points of a thermal zone. The cooling data reported > >> > will be absolute if the higher temperature trip points are arranged first > >> > otherwise the cooling stats is the cumulative effect of the earlier > >> > invoked cooling handlers. > >> > > >> > The basic assumption is that cooling devices will bring down the temperature > >> > in a symmetric manner and those statistics can be stored back and used for > >> > further tuning of the system. > >> > >> /sys fs should be one-value-per-file, talk to gregkh. > > > > That's correct. > > > > Why not use debugfs for this instead? > > > > thanks, > > > > greg k-h > > Thanks Greg/Pavel for looking into the patch. > Basically I checked the places where single sysfs entry is showing > more then 1 output. And > 1) /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state > 2) /sys/devices/system/cpu/cpu0/cpufreq/stats/trans_table > are the places where the output is more than 1 value. Yes, those are two known-bad files, whose files will change soon and move to debugfs. Just because you found 2, instead of the thousands of other properly formatted files, does not mean you are allowed to create something like this. > Anyway I can enclose this sysfs inside CONFIG_THERMAL_COOLING_STATS macro. No, you can not create it at all in sysfs, if you really need such a large single file, use debugfs instead, that is what it is there for. Again, one-value-per-file is the sysfs rule, and has been for a decade now, please don't think this is a new thing. greg k-h -- 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/