From owner-freebsd-current@FreeBSD.ORG Sun May 4 15:32:04 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 59FD1E29; Sun, 4 May 2014 15:32:04 +0000 (UTC) Received: from i3mail.icecube.wisc.edu (i3mail.icecube.wisc.edu [128.104.255.23]) by mx1.freebsd.org (Postfix) with ESMTP id 265AE1FA6; Sun, 4 May 2014 15:32:04 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by i3mail.icecube.wisc.edu (Postfix) with ESMTP id F09DC385B0; Sun, 4 May 2014 10:32:02 -0500 (CDT) X-Virus-Scanned: amavisd-new at icecube.wisc.edu Received: from i3mail.icecube.wisc.edu ([127.0.0.1]) by localhost (i3mail.icecube.wisc.edu [127.0.0.1]) (amavisd-new, port 10030) with ESMTP id kYogXP4FM9r1; Sun, 4 May 2014 10:32:02 -0500 (CDT) Received: from comporellon.tachypleus.net (polaris.tachypleus.net [75.101.50.44]) by i3mail.icecube.wisc.edu (Postfix) with ESMTPSA id 754A7385AF; Sun, 4 May 2014 10:32:02 -0500 (CDT) Message-ID: <53665D71.6060708@freebsd.org> Date: Sun, 04 May 2014 08:32:01 -0700 From: Nathan Whitehorn User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Adrian Chadd , Allan Jude Subject: Re: Leaving the Desktop Market References: <3F7430D7-3C0F-43E1-8EBD-8AA4F701497C@FreeBSD.org> <20140503155745.GA2457@La-Habana> <20140503192305.GA1847@La-Habana> <536592D1.7080403@freebsd.org> <5365C78E.6030600@allanjude.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 04 May 2014 15:32:04 -0000 On 05/03/14 22:29, Adrian Chadd wrote: > On 3 May 2014 21:52, Allan Jude wrote: > >>> * use cpufreq with some heuristics (like say, only step down to 2/3rd >>> the frequency if idle) - and document why that decision is made (eg on >>> CPU X, measuring Y at idle, power consumption was minimal at >>> frequency=Z.); >>> * make sure the lower frequencies and tcc kick in if a thermal cutoff >>> is reached; >>> * default to using lower Cx states out of the box if they're decided >>> to not be buggy. There are a few CPUs for which lower C states cause >>> problems but modernish hardware (say, nehalem and later) should be >>> fine. >> According to the wiki, in 9.x and onward there is code that is supposed >> to detect if the higher Cx states are usable, and not use them if they >> are not, but I do not know how well this works. > I'm not sure. I think those who care / know enough just put relevant > bits into /etc/rc.conf and /boot/loader.conf rather than flipping it > on by default. > > I'm kind of tempted to just flip on Cmax by default and teach powerd > to not do cpufreq unless there's a thermal issue. Then take a step > back and see what happens. > Please remember that powerd is not x86-only. Other systems (e.g. PowerPC) use it in conjunction with cpufreq. But seriously, let's just pull tcc from GENERIC. I'll do it next week unless I hear any objections. -Nathan