Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 3 Aug 2002 17:30:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 3 Aug 2002 17:30:21 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:50960 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Sat, 3 Aug 2002 17:30:20 -0400 Message-ID: <3D4C4E7A.C6707A4C@zip.com.au> Date: Sat, 03 Aug 2002 14:43:22 -0700 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.19-rc5 i686) X-Accept-Language: en MIME-Version: 1.0 To: Rik van Riel CC: Daniel Phillips , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Rmap speedup References: <3D4B692B.46817AD0@zip.com.au> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1210 Lines: 31 Rik van Riel wrote: > > On Fri, 2 Aug 2002, Andrew Morton wrote: > > > No joy, I'm afraid. > > > Guess we should instrument it up and make sure that the hashing > > and index thing is getting the right locality. > > Could it be that your quad needs to go to RAM to grab a cacheline > that's exclusive on the other CPU while Daniel's machine can just > shove cachelines from CPU to CPU ? Could be, Rik. I don't know. It's a bit worrisome that we might be dependent on subtleties like that. > What I'm referring to is the fact that the pte_chain_locks in > Daniel's patch are all packed into a few cachelines, instead of > having each lock on its own cache line... > > This could explain the fact that the locking overhead plummeted > on Daniel's box while it didn't change at all on your machine. Oh it helped a bit. More in 2.4 than 2.5. Possibly I broke Daniel's patch somehow. But even the improvement in 2.4 from Daniel's patch is disappointing. - 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/