From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1DUnAQ-0001oz-PR for user-mode-linux-devel@lists.sourceforge.net; Sun, 08 May 2005 07:54:02 -0700 Received: from colin.muc.de ([193.149.48.1] helo=mail.muc.de ident=qmailr) by sc8-sf-mx1.sourceforge.net with esmtp (TLSv1:AES256-SHA:256) (Exim 4.41) id 1DUnAP-0005Hy-4z for user-mode-linux-devel@lists.sourceforge.net; Sun, 08 May 2005 07:54:02 -0700 From: Andi Kleen Message-ID: <20050508145356.GB21873@muc.de> References: <20050507182728.GA29592@in.ibm.com> <1115524211.17482.23.camel@localhost.localdomain> <1115547230.5998.10.camel@laptopd505.fenrus.org> <1115559855.5998.26.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1115559855.5998.26.camel@laptopd505.fenrus.org> Subject: [uml-devel] Re: [RFC] (How to) Let idle CPUs sleep Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Sun, 8 May 2005 16:53:56 +0200 To: Arjan van de Ven Cc: vatsa@in.ibm.com, schwidefsky@de.ibm.com, jdike@addtoit.com, Andrew Morton , Ingo Molnar , Nick Piggin , rmk+lkml@arm.linux.org.uk, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net On Sun, May 08, 2005 at 03:44:14PM +0200, Arjan van de Ven wrote: > > > But it has to be *really* lightweight because these transistion can > > happen a lot (consider a CPU that very often goes to sleep for a short time) > > lightweight is good of course. But even if it's medium weight.. it just > means you need to be REALLY idle (eg for longer time) for it to trigger. > I guess we need some sort of per arch "idleness threshhold" for this. The question is how useful it is for the hypervisor to even know that. Why can't it just detect long idle periods by itself if it really wants? -Andi ------------------------------------------------------- This SF.Net email is sponsored by: NEC IT Guy Games. Get your fingers limbered up and give it your best shot. 4 great events, 4 opportunities to win big! Highest score wins.NEC IT Guy Games. Play to win an NEC 61 plasma display. Visit http://www.necitguy.com/?r=20 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262878AbVEHOyE (ORCPT ); Sun, 8 May 2005 10:54:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262879AbVEHOyE (ORCPT ); Sun, 8 May 2005 10:54:04 -0400 Received: from colin.muc.de ([193.149.48.1]:27910 "EHLO mail.muc.de") by vger.kernel.org with ESMTP id S262878AbVEHOyB (ORCPT ); Sun, 8 May 2005 10:54:01 -0400 Date: 8 May 2005 16:53:56 +0200 Date: Sun, 8 May 2005 16:53:56 +0200 From: Andi Kleen To: Arjan van de Ven Cc: vatsa@in.ibm.com, schwidefsky@de.ibm.com, jdike@addtoit.com, Andrew Morton , Ingo Molnar , Nick Piggin , rmk+lkml@arm.linux.org.uk, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net Subject: Re: [RFC] (How to) Let idle CPUs sleep Message-ID: <20050508145356.GB21873@muc.de> References: <20050507182728.GA29592@in.ibm.com> <1115524211.17482.23.camel@localhost.localdomain> <1115547230.5998.10.camel@laptopd505.fenrus.org> <1115559855.5998.26.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1115559855.5998.26.camel@laptopd505.fenrus.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 08, 2005 at 03:44:14PM +0200, Arjan van de Ven wrote: > > > But it has to be *really* lightweight because these transistion can > > happen a lot (consider a CPU that very often goes to sleep for a short time) > > lightweight is good of course. But even if it's medium weight.. it just > means you need to be REALLY idle (eg for longer time) for it to trigger. > I guess we need some sort of per arch "idleness threshhold" for this. The question is how useful it is for the hypervisor to even know that. Why can't it just detect long idle periods by itself if it really wants? -Andi