Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261346AbVALRiA (ORCPT ); Wed, 12 Jan 2005 12:38:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261345AbVALRiA (ORCPT ); Wed, 12 Jan 2005 12:38:00 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:35560 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S261271AbVALRhs (ORCPT ); Wed, 12 Jan 2005 12:37:48 -0500 Date: Wed, 12 Jan 2005 09:37:27 -0800 (PST) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Christoph Hellwig cc: Andrew Morton , Nick Piggin , torvalds@osdl.org, ak@muc.de, hugh@veritas.com, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org Subject: Re: page table lock patch V15 [0/7]: overview In-Reply-To: <20050112164906.GA4935@infradead.org> Message-ID: References: <41E4BCBE.2010001@yahoo.com.au> <20050112014235.7095dcf4.akpm@osdl.org> <20050112164906.GA4935@infradead.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1721 Lines: 38 On Wed, 12 Jan 2005, Christoph Hellwig wrote: > On Wed, Jan 12, 2005 at 08:39:21AM -0800, Christoph Lameter wrote: > > The future is in higher and higher SMP counts since the chase for the > > higher clock frequency has ended. We will increasingly see multi-core > > cpus etc. Machines with higher CPU counts are becoming common in business. > > An they still are absolutely in the minority. In fact with multicore > cpus it becomes more and more important to be fast for SMP systtems with > a _small_ number of CPUs, while really larget CPUs will remain a small > nische for the forseeable future. The benefits start to be significant pretty fast with even a few cpus on modern architectures: Altix no patch: Gb Rep Threads User System Wall flt/cpu/s fault/wsec 1 10 1 0.107s 6.444s 6.055s100028.084 100006.622 1 10 2 0.121s 9.048s 4.082s 71468.414 135904.412 1 10 4 0.129s 10.185s 3.011s 63531.985 210146.600 w/patch Gb Rep Threads User System Wall flt/cpu/s fault/wsec 1 10 1 0.094s 6.116s 6.021s105517.039 105517.574 1 10 2 0.134s 6.998s 3.087s 91879.573 169079.712 1 10 4 0.095s 7.658s 2.043s 84519.939 268955.165 There is even a small benefit to the single thread case. Its not the case that this patch only benefits systems with a large number of CPUs. Of course that is when the benefits results in performance gains by orders of magnitude. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/