From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Lee Irwin III Date: Sat, 20 Nov 2004 02:04:01 +0000 Subject: Re: page fault scalability patch V11 [0/7]: overview Message-Id: <20041120020401.GC2714@holomorphy.com> List-Id: References: <419D581F.2080302@yahoo.com.au> <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Lameter Cc: torvalds@osdl.org, akpm@osdl.org, Benjamin Herrenschmidt , Nick Piggin , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org On Fri, Nov 19, 2004 at 11:42:39AM -0800, Christoph Lameter wrote: > A. make_rss_atomic. The earlier releases contained that patch but > then another variable (such as anon_rss) was introduced that would > have required additional atomic operations. Atomic rss operations > are also causing slowdowns on machines with a high number of cpus > due to memory contention. > B. remove_rss. Replace rss with a periodic scan over the vm to > determine rss and additional numbers. This was also discussed on > linux-mm and linux-ia64. The scans while displaying /proc data > were undesirable. Split counters easily resolve the issues with both these approaches (and apparently your co-workers are suggesting it too, and have performance results backing it). -- wli From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261712AbUKTCLR (ORCPT ); Fri, 19 Nov 2004 21:11:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262812AbUKTCFz (ORCPT ); Fri, 19 Nov 2004 21:05:55 -0500 Received: from holomorphy.com ([207.189.100.168]:28544 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S262823AbUKTCEJ (ORCPT ); Fri, 19 Nov 2004 21:04:09 -0500 Date: Fri, 19 Nov 2004 18:04:01 -0800 From: William Lee Irwin III To: Christoph Lameter Cc: torvalds@osdl.org, akpm@osdl.org, Benjamin Herrenschmidt , Nick Piggin , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: page fault scalability patch V11 [0/7]: overview Message-ID: <20041120020401.GC2714@holomorphy.com> References: <419D581F.2080302@yahoo.com.au> <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 19, 2004 at 11:42:39AM -0800, Christoph Lameter wrote: > A. make_rss_atomic. The earlier releases contained that patch but > then another variable (such as anon_rss) was introduced that would > have required additional atomic operations. Atomic rss operations > are also causing slowdowns on machines with a high number of cpus > due to memory contention. > B. remove_rss. Replace rss with a periodic scan over the vm to > determine rss and additional numbers. This was also discussed on > linux-mm and linux-ia64. The scans while displaying /proc data > were undesirable. Split counters easily resolve the issues with both these approaches (and apparently your co-workers are suggesting it too, and have performance results backing it). -- wli From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 19 Nov 2004 18:04:01 -0800 From: William Lee Irwin III Subject: Re: page fault scalability patch V11 [0/7]: overview Message-ID: <20041120020401.GC2714@holomorphy.com> References: <419D581F.2080302@yahoo.com.au> <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: torvalds@osdl.org, akpm@osdl.org, Benjamin Herrenschmidt , Nick Piggin , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: On Fri, Nov 19, 2004 at 11:42:39AM -0800, Christoph Lameter wrote: > A. make_rss_atomic. The earlier releases contained that patch but > then another variable (such as anon_rss) was introduced that would > have required additional atomic operations. Atomic rss operations > are also causing slowdowns on machines with a high number of cpus > due to memory contention. > B. remove_rss. Replace rss with a periodic scan over the vm to > determine rss and additional numbers. This was also discussed on > linux-mm and linux-ia64. The scans while displaying /proc data > were undesirable. Split counters easily resolve the issues with both these approaches (and apparently your co-workers are suggesting it too, and have performance results backing it). -- wli -- 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: aart@kvack.org