From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] report revision 3 of the ACPI/SMBus PIIX4 controller Date: Sun, 13 Jan 2008 12:25:18 +0200 Message-ID: <4789E70E.7040802@qumranet.com> References: <20080111212655.GA28753@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org To: Marcelo Tosatti Return-path: In-Reply-To: <20080111212655.GA28753@dmt> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Marcelo Tosatti wrote: > The PIIX4 ACPI controller prior to revision 0x3 contains a bug where > reading of the timer port is unreliable, so the kernel reads it three > times for consistency check. > > QEMU does not suffer from that problem :) > > The datasheet for PIIX4, PIIX4E, and PIIX4M is the same. I failed to > find any indication that the revision increase could affect anything > other than the PMTimer port read. > > This reduces idle guest CPU consumption from 14% to 8% on 4-way KVM > guest. > > Applied (to kvm's qemu), thanks. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace