From owner-freebsd-stable@FreeBSD.ORG Fri May 22 18:47:59 2015 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 1EE76240; Fri, 22 May 2015 18:47:59 +0000 (UTC) Received: from mail-ie0-x234.google.com (mail-ie0-x234.google.com [IPv6:2607:f8b0:4001:c03::234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id DD33C1CC2; Fri, 22 May 2015 18:47:58 +0000 (UTC) Received: by iebgx4 with SMTP id gx4so37644045ieb.0; Fri, 22 May 2015 11:47:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=cWLj6dAptnh500IXPj5u2fxdo2MB/1l2qJSut+8+iSc=; b=Mx9haUyj3WDFZl3jnKozeyhAv9TIDEAfIHrRgVKv/L2527dIbv+TytgNIVrqz7Q+f0 4spdO8StNmCcfaxxchwgDa8XLMh0auhrmt/osI1UbXMyuIGQ88kPSrPfXUIg99hzoXFL hEVN3RuOwYD5w7c1/AmLEU0e0mg20CA/wOwx+vfpgJNKeAwltXVATSgH/CS6RhnjM6K6 9k0f3WgfLh9n5oXPxIVUvgm9jd+yxmCHYigVDbnfGoxwVjwoJzmUlA8cJW4/H8jD/n1J 7jj3dzknuYs1HuIpP/hXjDKJqF5xMdoI5CPr1RfCfD1O7yXaQO3VQJCltTKEoVaEndlZ FwMw== MIME-Version: 1.0 X-Received: by 10.50.114.9 with SMTP id jc9mr7460344igb.49.1432320478293; Fri, 22 May 2015 11:47:58 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.36.38.133 with HTTP; Fri, 22 May 2015 11:47:58 -0700 (PDT) In-Reply-To: <555F7599.5000605@freebsd.org> References: <555C71C8.4080007@gmx.com> <555EDBBB.4090107@gmx.com> <555F7599.5000605@freebsd.org> Date: Fri, 22 May 2015 11:47:58 -0700 X-Google-Sender-Auth: l7BGVcMt0wlomc0WHCFqXCmnsXw Message-ID: Subject: Re: CPU frequency doesn't drop below 1200MHz (like it used to) From: Adrian Chadd To: Stefan Esser Cc: Nikos Vassiliadis , freebsd-stable Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 May 2015 18:47:59 -0000 Hi, The whole point of throttling on modern hardware isn't to get really low clock rates, it's to deal with being out of thermal envelope. But, the modern intel cores will do that for you without OS involvement. So, you don't have to actually use p4tcc and it may actually configure your hardware wrong. Just throttle down to 1200MHz and go into deeper sleep states (>C1). I checked this on a variety of older and modern hardware; they all worked better just doing lowest ACPI P state and lowest ACPI C state. -adrian