From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752535Ab1GTQSD (ORCPT ); Wed, 20 Jul 2011 12:18:03 -0400 Received: from smtp106.prem.mail.ac4.yahoo.com ([76.13.13.45]:38596 "HELO smtp106.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752458Ab1GTQSB (ORCPT ); Wed, 20 Jul 2011 12:18:01 -0400 X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 7AGrbMYVM1m4.GGnujBGHEGKZ4to58f5ZYyi7MXr.IIuO7N 1eJ7HmEhf2zTmJADcsdTLDsquH817WiiGEnHhUK665NQpAkqJJ8NzGx8XMQU vazk2LIycsBAc6eT.e34kDl_qyxtt.CClfIHaZmQeresvcqR8Bjcy_Qs7P7P LhzCHErhM93M0jTSplwTiJQjgYU1JgOS6qgJ7Ci2wrJQ7UbaPQmf5fXXAO9P ZzR76ojasqdcldensSTJrjYYZWtVrGIpyuFw5o.j1oG4Sad5KVogTDcuqmgE 47HuNm3J28EQoAJsRaOwFO8PGQOwqSWUx4Z744223PcR1tQRlYbo_YD_BvxF LbSLQx67FjTvSAr5m3YfHXIfQ X-Yahoo-SMTP: _Dag8S.swBC1p4FJKLCXbs8NQzyse1SYSgnAbY0- Date: Wed, 20 Jul 2011 11:17:57 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@router.home To: Eric Dumazet cc: Mel Gorman , Pekka Enberg , Konstantin Khlebnikov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Matt Mackall Subject: Re: [PATCH] mm-slab: allocate kmem_cache with __GFP_REPEAT In-Reply-To: <1311177362.2338.57.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Message-ID: References: <20110720121612.28888.38970.stgit@localhost6> <20110720134342.GK5349@suse.de> <1311170893.2338.29.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1311174562.2338.42.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1311177362.2338.57.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Jul 2011, Eric Dumazet wrote: > Note that adding ____cacheline_aligned_in_smp on nodelists[] actually > helps performance, as all following fields are readonly after kmem_cache > setup. Well but that is not addresssing the same issue. Could you separate that out? The other question that follows from this is then: Does that alignment compensate for the loss of performance due to the additional lookup in hot code paths and the additional cacheline reference required? The per node pointers are lower priority in terms of performance than the per cpu pointers. I'd rather have the per node pointers requiring an additional lookup. Less impact on hot code paths. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 41E9B6B004A for ; Wed, 20 Jul 2011 12:18:02 -0400 (EDT) Date: Wed, 20 Jul 2011 11:17:57 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH] mm-slab: allocate kmem_cache with __GFP_REPEAT In-Reply-To: <1311177362.2338.57.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Message-ID: References: <20110720121612.28888.38970.stgit@localhost6> <20110720134342.GK5349@suse.de> <1311170893.2338.29.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1311174562.2338.42.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1311177362.2338.57.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: Mel Gorman , Pekka Enberg , Konstantin Khlebnikov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Matt Mackall On Wed, 20 Jul 2011, Eric Dumazet wrote: > Note that adding ____cacheline_aligned_in_smp on nodelists[] actually > helps performance, as all following fields are readonly after kmem_cache > setup. Well but that is not addresssing the same issue. Could you separate that out? The other question that follows from this is then: Does that alignment compensate for the loss of performance due to the additional lookup in hot code paths and the additional cacheline reference required? The per node pointers are lower priority in terms of performance than the per cpu pointers. I'd rather have the per node pointers requiring an additional lookup. Less impact on hot code paths. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org