Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263904AbUDFQkb (ORCPT ); Tue, 6 Apr 2004 12:40:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263902AbUDFQka (ORCPT ); Tue, 6 Apr 2004 12:40:30 -0400 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:40584 "EHLO dualathlon.random") by vger.kernel.org with ESMTP id S263904AbUDFQjx (ORCPT ); Tue, 6 Apr 2004 12:39:53 -0400 Date: Tue, 6 Apr 2004 18:39:50 +0200 From: Andrea Arcangeli To: Arjan van de Ven Cc: Ingo Molnar , Eric Whiting , akpm@osdl.org, linux-kernel@vger.kernel.org, Pete Zaitcev Subject: Re: -mmX 4G patches feedback [numbers: how much performance impact] Message-ID: <20040406163950.GA2234@dualathlon.random> References: <40718B2A.967D9467@amis.com> <20040405174616.GH2234@dualathlon.random> <4071D11B.1FEFD20A@amis.com> <20040405221641.GN2234@dualathlon.random> <20040406115539.GA31465@elte.hu> <20040406155925.GW2234@dualathlon.random> <1081268018.4680.6.camel@laptop.fenrus.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1081268018.4680.6.camel@laptop.fenrus.com> User-Agent: Mutt/1.4.1i X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1250 Lines: 23 On Tue, Apr 06, 2004 at 06:13:39PM +0200, Arjan van de Ven wrote: > On Tue, 2004-04-06 at 17:59, Andrea Arcangeli wrote: > > > You should also use a bleeding edge cpu for you measurements with large > > tlb caches, which cpu did you use for your measurements? > > afaics all Intel and AMD cpus with more than say 32 or 64 TLB's are > actually 64 bit capable.... so obviously you run a 64 bit kernel there. > (and amd64 even has that sweet CAM filter on the tlbs to mitigate the > effect even if you run a 32 bit kernel) I simply heard the effect was less visible on PIII than on more recent cpus, but maybe that was wrong. Do you have any result comparing different cpus (I mean with realistic tests not stuff like loop_print.c doing nothing but rdtsc)? It'd be most interesting to see the effect on hugetlbfs, to get past a certain amount of ram hugetlbfs is needed for performance reasons (plus it avoids the costs of the pte saving ram, but that's a secondary benefit, ptes are in highmem anyways). - 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/