From owner-freebsd-acpi@FreeBSD.ORG Fri Nov 14 01:24:37 2008 Return-Path: Delivered-To: freebsd-acpi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 626161065670 for ; Fri, 14 Nov 2008 01:24:37 +0000 (UTC) (envelope-from cnszym@gmail.com) Received: from ey-out-2122.google.com (ey-out-2122.google.com [74.125.78.25]) by mx1.freebsd.org (Postfix) with ESMTP id DCBB48FC0A for ; Fri, 14 Nov 2008 01:24:36 +0000 (UTC) (envelope-from cnszym@gmail.com) Received: by ey-out-2122.google.com with SMTP id 6so501911eyi.7 for ; Thu, 13 Nov 2008 17:24:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=IfWc3BIII/AcDqLnVq6C4QOEfesxt0G6JrhtKpCU1Hs=; b=oRKnZANY4LxkmGQk5sSC8xsynTb4//pagfMrLIySg9goV5sMgoUQ+GWYHXpv8VqXvK f5cuTh+/oNoMLOSviEGgFih92SCQRM6lfAz6bRPsfev0r91RnjrenmKsETcaUghB4Hay C4BtVJQr028l2nl8QH4X0VvmRca69KEMdGLRY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=adqxfB4AuoiAHAw8D1X3xCsdesPjGNCDUcAOSw23TMG1F53iRda6Z5vXZwPE3DJSnr jJg46UQ4Wq2K6cKJquSwOw8DNl5MzH8i1UGlLfImv3Dv5nGDP+XYq8AXMGmalqVLVTFd OnkMoXP6xEeQo03EshKKA+fYmYmgzPtf3h3Cc= Received: by 10.210.141.4 with SMTP id o4mr385517ebd.3.1226624129943; Thu, 13 Nov 2008 16:55:29 -0800 (PST) Received: by 10.210.43.20 with HTTP; Thu, 13 Nov 2008 16:55:29 -0800 (PST) Message-ID: Date: Fri, 14 Nov 2008 09:55:29 +0900 From: "Cyrille Szymanski" To: "Alexander Motin" In-Reply-To: <49189B47.7090509@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <491404BF.1090807@FreeBSD.org> <49186111.9020103@root.org> <49189B47.7090509@FreeBSD.org> Cc: FreeBSD acpi Subject: Re: RFC: powerd algorithms enhancements X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Nov 2008 01:24:37 -0000 2008/11/11 Alexander Motin : > Universality and predictiveness. Systems with 2 and with 32 levels will > drop/rise frequency with same absolute rate. If we are trying to speak about > some comparing, algorithm should be hardware independent. Hi The heuristics PAST and FLAT are two examples of strategies which do just this : they determine the desired operating frequency (in Hz) and then switch to the closest level available. >> There's a patch Cyrille Szymanski has sent me to review that implements >> the FLAT and PAST algorithms in powerd. I think we should not add new >> modes that are heuristics (including this one) until we have a chance to >> compare it to algorithms that have been the result of real research. > > So show it to us. This area is heuristic by default as there is several > opposite criteriums, so any algorithm will be heuristic. Although I see the benefits of your proposal, and reckon that systems with may levels are more and more common these days. The point is, I think, to avoid adding tuning knobs to powerd that would be too specific to your configuration and which might benefit everyone. Research will (I hope) indicate the way to go. Thanks ! -- Cyrille Szymanski