From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH] ACPI: Fix the incorrect calculation about C-state idle time Date: Wed, 2 Jun 2010 16:06:59 +0100 Message-ID: <20100602150659.GA5335@srcf.ucam.org> References: <1275447849-25761-1-git-send-email-yakui.zhao@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:47643 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758389Ab0FBPHK (ORCPT ); Wed, 2 Jun 2010 11:07:10 -0400 Content-Disposition: inline In-Reply-To: <1275447849-25761-1-git-send-email-yakui.zhao@intel.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: yakui.zhao@intel.com Cc: lenb@kernel.org, linux-acpi@vger.kernel.org, Venkatesh Pallipadi On Wed, Jun 02, 2010 at 11:04:09AM +0800, yakui.zhao@intel.com wrote: > From: Zhao Yakui > > The C-state idle time is not calculated correctly, which will return the wrong > residency time in C-state. It will have the following effects: > 1. The system can't choose the deeper C-state when it is idle next time. > Of course the system power is increased. E.g. On one server machine about 40W > idle power is increased. > 2. The powertop shows that it will stay in C0 running state about 95% time > although the system is idle at most time. What kind of system was this seen on? -- Matthew Garrett | mjg59@srcf.ucam.org