From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f43.google.com (mail-pa0-f43.google.com [209.85.220.43]) by kanga.kvack.org (Postfix) with ESMTP id 5D2FB6B0055 for ; Wed, 25 Sep 2013 21:21:33 -0400 (EDT) Received: by mail-pa0-f43.google.com with SMTP id hz1so570758pad.30 for ; Wed, 25 Sep 2013 18:21:33 -0700 (PDT) Date: Wed, 25 Sep 2013 18:21:29 -0700 From: Andrew Morton Subject: Re: [Results] [RFC PATCH v4 00/40] mm: Memory Power Management Message-Id: <20130925182129.a7db6a0fd2c7cc3b43fda92d@linux-foundation.org> In-Reply-To: <52438AA9.3020809@linux.intel.com> References: <20130925231250.26184.31438.stgit@srivatsabhat.in.ibm.com> <52437128.7030402@linux.vnet.ibm.com> <20130925164057.6bbaf23bdc5057c42b2ab010@linux-foundation.org> <20130925234734.GK18242@two.firstfloor.org> <52438AA9.3020809@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Arjan van de Ven Cc: Andi Kleen , "Srivatsa S. Bhat" , mgorman@suse.de, dave@sr71.net, hannes@cmpxchg.org, tony.luck@intel.com, matthew.garrett@nebula.com, riel@redhat.com, srinivas.pandruvada@linux.intel.com, willy@linux.intel.com, kamezawa.hiroyu@jp.fujitsu.com, lenb@kernel.org, rjw@sisk.pl, gargankita@gmail.com, paulmck@linux.vnet.ibm.com, svaidy@linux.vnet.ibm.com, isimatu.yasuaki@jp.fujitsu.com, santosh.shilimkar@ti.com, kosaki.motohiro@gmail.com, linux-pm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, 25 Sep 2013 18:15:21 -0700 Arjan van de Ven wrote: > On 9/25/2013 4:47 PM, Andi Kleen wrote: > >> Also, the changelogs don't appear to discuss one obvious downside: the > >> latency incurred in bringing a bank out of one of the low-power states > >> and back into full operation. Please do discuss and quantify that to > >> the best of your knowledge. > > > > On Sandy Bridge the memry wakeup overhead is really small. It's on by default > > in most setups today. > > btw note that those kind of memory power savings are content-preserving, > so likely a whole chunk of these patches is not actually needed on SNB > (or anything else Intel sells or sold) (head spinning a bit). Could you please expand on this rather a lot? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org