From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 16 Oct 2006 03:26:32 -0700 From: Paul Jackson Subject: Re: [TAKE] memory page_alloc zonelist caching speedup Message-Id: <20061016032632.486f4235.pj@sgi.com> In-Reply-To: <200610161134.07168.ak@suse.de> References: <20061010081429.15156.77206.sendpatchset@jackhammer.engr.sgi.com> <200610161134.07168.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: linux-mm@kvack.org, akpm@osdl.org, nickpiggin@yahoo.com.au, rientjes@google.com, mbligh@google.com, rohitseth@google.com, menage@google.com, clameter@sgi.com List-ID: Andi wrote: > I think some more precise numbers would be appreciated before doing > such changes. Aren't there more precise numbers further down in the message to which you were responding? > Yes but you will add latencies for cache line bounces won't you? > The old zone lists were completely read only. That is what worries me > most. There is one zonelist_cache per node, added at the end of the regular zonelist array for each node. It will have a few words updated typically at the rate of once per second by the CPUs sharing that node. >>From what my tests showed, and from what I'd expect, updating a few node local words per second is not a problem. If you have a particular architecture in mind for which the tradeoffs in the proposed patch don't seem right, could you spell out that architecture a bit, so we can sensibly consider whether some refinements to this patch will suit that architecture better? Certainly, from the numbers that I have, and by private email that Rohit Seth has on a different architecture, this patch is neutral or a win for the cases we considered, depending on the degree of node locality of the memory accesses. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401 -- 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