From owner-freebsd-acpi@FreeBSD.ORG Fri Feb 1 15:37:50 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 AF90616A418 for ; Fri, 1 Feb 2008 15:37:50 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from falcon.cybervisiontech.com (falcon.cybervisiontech.com [217.20.163.9]) by mx1.freebsd.org (Postfix) with ESMTP id 5F9F513C44B for ; Fri, 1 Feb 2008 15:37:50 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from localhost (localhost [127.0.0.1]) by falcon.cybervisiontech.com (Postfix) with ESMTP id A6B3C43C586; Fri, 1 Feb 2008 17:37:48 +0200 (EET) X-Virus-Scanned: Debian amavisd-new at falcon.cybervisiontech.com Received: from falcon.cybervisiontech.com ([127.0.0.1]) by localhost (falcon.cybervisiontech.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QKBX7xHJ8xAe; Fri, 1 Feb 2008 17:37:48 +0200 (EET) Received: from [10.2.1.87] (gateway.cybervisiontech.com.ua [88.81.251.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by falcon.cybervisiontech.com (Postfix) with ESMTP id 47EEC43C252; Fri, 1 Feb 2008 17:37:48 +0200 (EET) Message-ID: <47A33CCB.3090902@icyb.net.ua> Date: Fri, 01 Feb 2008 17:37:47 +0200 From: Andriy Gapon User-Agent: Thunderbird 2.0.0.9 (X11/20080123) MIME-Version: 1.0 To: Nate Lawson References: <479F0ED4.9030709@icyb.net.ua> <479F62D9.6080703@root.org> In-Reply-To: <479F62D9.6080703@root.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: freebsd-acpi@freebsd.org Subject: Re: cx_lowest and CPU usage 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, 01 Feb 2008 15:37:50 -0000 on 29/01/2008 19:31 Nate Lawson said the following: > Andriy Gapon wrote: >> Report for 7.0-RC1 on quite old hardware: 440BX-based motherboard, >> 450Mhz Pentium III (Katmai). >> >> cx_supported claims to support C1, C2, C3. If I set cx_lowest to C3 it >> immediately gets backed out to C2 with a kernel message about too many >> short sleeps. But that's not a problem. >> There is a weird thing: if I change cx_lowest to C2 when the machine is >> completely idle, top shows that CPU usage for interrupts immediately >> jumps to almost 20%. Change cx_lowest to C1, CPU usage drops back to >> almost 0%. >> Is this normal ? >> If not, does this indicate some problem in idle routine or is this just >> incorrect statistics calculation ? Or maybe something with HW ? > > Leave it at C1. Apparently C2 and C3 don't work on your machine. > That's understandable with older, non-laptop hw. Nate, I understand the advice. I event see that the code has the following comment "Disable C3 support for all PIIX4 chipsets", but apparently it does a little bit different thing. Out of curiosity, what could be wrong with C2 state ? vmstat -i reports identical interrupt rates with both cx_lowest=C1 and cx_lowest=C2, so I wonder where from the extra interrupt CPU utilization comes. -- Andriy Gapon