Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264210AbUDGXDw (ORCPT ); Wed, 7 Apr 2004 19:03:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261206AbUDGXDw (ORCPT ); Wed, 7 Apr 2004 19:03:52 -0400 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:19901 "EHLO dualathlon.random") by vger.kernel.org with ESMTP id S264211AbUDGXBl (ORCPT ); Wed, 7 Apr 2004 19:01:41 -0400 Date: Thu, 8 Apr 2004 01:01:40 +0200 From: Andrea Arcangeli To: "Martin J. Bligh" Cc: Ingo Molnar , Eric Whiting , akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: -mmX 4G patches feedback [numbers: how much performance impact] Message-ID: <20040407230140.GT26888@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> <20040406192549.GA14869@elte.hu> <12640000.1081378705@flay> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12640000.1081378705@flay> 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: 1233 Lines: 22 On Wed, Apr 07, 2004 at 03:58:25PM -0700, Martin J. Bligh wrote: > so .... such microbenchmarks seems pointless. I'm not against 4/4G at all, > I think it solves a real problem ... I just think latency numbers are a I agree as well it solves a real problem (i.e. 4G userspace), though the userbase that needs it is extremely limited and they're sure ok to run slower than to change their application to use shmfs (a special 4:4 kernel may be ok, just like a special 2.5:1.5 may be ok, just like 3.5:0.5 was ok for similar reasons too), but the mass market doesn't need 4:4 and it will never need it, so it's bad to have the masses pay for this relevant worthless runtime overhead in various common workloads. Of course above I'm talking about 2.6-aa or 2.6-mjb. Clearly with kernels including rmap like 2.6 mainline or 2.6-mm or 2.6-mc or the 2.4-rmap patches you need 4:4 everywhere, even on a 4/8G box to avoid running out of normal zone in some fairly common and important workload. - 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/