From owner-freebsd-arch@FreeBSD.ORG Tue May 6 22:15:51 2014 Return-Path: Delivered-To: freebsd-arch@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 C9A79D3; Tue, 6 May 2014 22:15:51 +0000 (UTC) Received: from mho-01-ewr.mailhop.org (mho-03-ewr.mailhop.org [204.13.248.66]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 9C33EB99; Tue, 6 May 2014 22:15:50 +0000 (UTC) Received: from c-24-8-230-52.hsd1.co.comcast.net ([24.8.230.52] helo=damnhippie.dyndns.org) by mho-01-ewr.mailhop.org with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.72) (envelope-from ) id 1WhneP-000KW2-7n; Tue, 06 May 2014 22:15:49 +0000 Received: from [172.22.42.240] (revolution.hippie.lan [172.22.42.240]) by damnhippie.dyndns.org (8.14.3/8.14.3) with ESMTP id s46MFkFj026622; Tue, 6 May 2014 16:15:46 -0600 (MDT) (envelope-from ian@FreeBSD.org) X-Mail-Handler: Dyn Standard SMTP by Dyn X-Originating-IP: 24.8.230.52 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/sendlabs/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1+8kRswA9DWBxTt4D8kCWJI Subject: Re: proposal: set default lid state to S3, performance/economy Cx states to Cmax From: Ian Lepore To: John Baldwin In-Reply-To: <201405061637.30037.jhb@freebsd.org> References: <201405051657.49992.jhb@freebsd.org> <201405061637.30037.jhb@freebsd.org> Content-Type: text/plain; charset="us-ascii" Date: Tue, 06 May 2014 16:15:46 -0600 Message-ID: <1399414546.22079.286.camel@revolution.hippie.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 FreeBSD GNOME Team Port Content-Transfer-Encoding: 7bit Cc: Kevin Oberman , Adrian Chadd , "freebsd-acpi@freebsd.org" , "freebsd-arch@freebsd.org" X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 May 2014 22:15:51 -0000 On Tue, 2014-05-06 at 16:37 -0400, John Baldwin wrote: > On Tuesday, May 06, 2014 2:08:35 pm Adrian Chadd wrote: > > On 5 May 2014 13:57, John Baldwin wrote: > > > > > The user in question found this on 9-stable with the existing defaults as the > > > HPET was just plain broken on their system and that was unrelated to Cx states. > > > (Rather, Cx states were only involved because worries about them are why the > > > system chose to use HPET. Had Cx states been enabled by default, they would > > > have had to disable those as well in addition to forcing LAPIC instead of > > > HPET.) > > > > Hm. Sounds uncomfortable. How does Windows run on systems like this? > > Do the windows drivers just disable HPET and use LAPIC or worse for > > timing, and just ignore anything lower than C1? > > I have no idea. Maybe they use the RTC. :-/ Maybe the HPET on these systems > works if you use it "sparingly". I believe OS X might have only used the HPET > to provide the "missing" LAPIC wakeups when entering Cx for example. (Our current > eventtimer system wants to always use whichever timer it picks, not switch off > between them.) > The eventtimer code is happy to switch between timers on the fly, but iirc the only interface to that feature is sysctl. I found it fairly easy to add an in-kernel API for changing the frequency of the current timer on the fly. I think it would be just as easy to add a kernel call to change timers as well. -- Ian