From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751900Ab1F3Eif (ORCPT ); Thu, 30 Jun 2011 00:38:35 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:37648 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750749Ab1F3Ei2 (ORCPT ); Thu, 30 Jun 2011 00:38:28 -0400 Date: Thu, 30 Jun 2011 10:07:59 +0530 From: Ankita Garg To: Vaidyanathan Srinivasan Cc: Dave Hansen , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, thomas.abraham@linaro.org, "Paul E. McKenney" , KAMEZAWA Hiroyuki , Matthew Garrett , Arjan van de Ven Subject: Re: [PATCH 00/10] mm: Linux VM Infrastructure to support Memory Power Management Message-ID: <20110630043759.GA12667@in.ibm.com> Reply-To: Ankita Garg References: <1306499498-14263-1-git-send-email-ankita@in.ibm.com> <20110629130038.GA7909@in.ibm.com> <1309367184.11430.594.camel@nimitz> <20110629174220.GA9152@in.ibm.com> <1309370342.11430.604.camel@nimitz> <20110629181755.GG3646@dirshya.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110629181755.GG3646@dirshya.in.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 29, 2011 at 11:47:55PM +0530, Vaidyanathan Srinivasan wrote: > * Dave Hansen [2011-06-29 10:59:02]: > > > On Wed, 2011-06-29 at 23:12 +0530, Ankita Garg wrote: > > > > 5. Being able to group these pieces of hardware for purpose of > > > higher savings. > > > > Do you really mean group, or do you mean "turn as many off as possible"? > > Grouping based on hardware topology could help save more power at > higher granularity. In most cases just turning as many off as > possible will work. But the design should allow grouping based on > certain rules or hierarchies. > For instance, on the Samsung Exynos 4210 board, the controller dynamically transitions 512MB of memory into lower powerdown state depending on whether it is being actively referenced or not. Additionally, if two such 512MB devices are free (as hinted by software), the controller can cut the clock going into that memory channel to which the two devices are connected, further reducing the power consumption. -- Regards, eAnkita Garg (ankita@in.ibm.com) Linux Technology Center IBM India Systems & Technology Labs, Bangalore, India