From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 2 Mar 2007 10:02:57 -0800 From: Andrew Morton Subject: Re: The performance and behaviour of the anti-fragmentation related patches Message-Id: <20070302100257.fd0d44a8.akpm@linux-foundation.org> In-Reply-To: <20070302173527.GA7280@linux.intel.com> References: <20070301101249.GA29351@skynet.ie> <20070301160915.6da876c5.akpm@linux-foundation.org> <45E7835A.8000908@in.ibm.com> <20070301195943.8ceb221a.akpm@linux-foundation.org> <20070302162023.GA4691@linux.intel.com> <20070302090753.b06ed267.akpm@linux-foundation.org> <20070302173527.GA7280@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: mgross@linux.intel.com Cc: Linus Torvalds , Balbir Singh , Mel Gorman , npiggin@suse.de, clameter@engr.sgi.com, mingo@elte.hu, jschopp@austin.ibm.com, arjan@infradead.org, mbligh@mbligh.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, 2 Mar 2007 09:35:27 -0800 Mark Gross wrote: > > > > Will it be possible to just power the DIMMs off? I don't see much point in > > some half-power non-destructive mode. > > I think so, but need to double check with the HW folks. > > Technically, the dims could be powered off, and put into 2 different low > power non-destructive states. (standby and suspend), but putting them > in a low power non-destructive mode has much less latency and provides > good bang for the buck or LOC change needed to make work. > > Which lower power mode an application chooses will depend on latency > tolerances of the app. For the POC activities we are looking at we are > targeting the lower latency option, but that doesn't lock out folks from > trying to do something with the other options. > If we don't evacuate all live data from all of the DIMM, we'll never be able to power the thing down in many situations. Given that we _have_ emptied the DIMM, we can just turn it off. And refilling it will be slow - often just disk speed. So I don't see a useful use-case for non-destructive states. -- 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