From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263112AbUKTDsn (ORCPT ); Fri, 19 Nov 2004 22:48:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263114AbUKTDqv (ORCPT ); Fri, 19 Nov 2004 22:46:51 -0500 Received: from holomorphy.com ([207.189.100.168]:31873 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S263070AbUKTDoD (ORCPT ); Fri, 19 Nov 2004 22:44:03 -0500 Date: Fri, 19 Nov 2004 19:43:49 -0800 From: William Lee Irwin III To: Nick Piggin Cc: Christoph Lameter , torvalds@osdl.org, akpm@osdl.org, Benjamin Herrenschmidt , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Robin Holt Subject: Re: page fault scalability patch V11 [0/7]: overview Message-ID: <20041120034349.GG2714@holomorphy.com> References: <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> <20041120020401.GC2714@holomorphy.com> <419EA96E.9030206@yahoo.com.au> <20041120023443.GD2714@holomorphy.com> <419EAEA8.2060204@yahoo.com.au> <20041120030425.GF2714@holomorphy.com> <419EB699.4050204@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <419EB699.4050204@yahoo.com.au> 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 William Lee Irwin III wrote: >> Irrelevant. Unshare cachelines with hot mm-global ones, and the >> "problem" goes away. On Sat, Nov 20, 2004 at 02:14:33PM +1100, Nick Piggin wrote: > That's the idea. William Lee Irwin III wrote: >> This stuff is going on and on about some purist "no atomic operations >> anywhere" weirdness even though killing the last atomic operation >> creates problems and doesn't improve performance. On Sat, Nov 20, 2004 at 02:14:33PM +1100, Nick Piggin wrote: > Huh? How is not wanting to impact single threaded performance being > "purist weirdness"? Practical, I'd call it. Empirically demonstrate the impact on single-threaded performance. On Sat, Nov 20, 2004 at 01:40:40PM +1100, Nick Piggin wrote: >> Why the Hell would you bother giving each cpu a separate cacheline? >> The odds of bouncing significantly merely amongst the counters are not >> particularly high. On Sat, Nov 20, 2004 at 02:14:33PM +1100, Nick Piggin wrote: > Hmm yeah I guess wouldn't put them all on different cachelines. > As you can see though, Christoph ran into a wall at 8 CPUs, so > having them densly packed still might not be enough. Please be more specific about the result, and cite the Message-Id. -- wli