From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 416FA1381F3 for ; Mon, 17 Dec 2012 09:10:54 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 43594E04ED; Mon, 17 Dec 2012 09:10:39 +0000 (UTC) Received: from mail-oa0-f53.google.com (mail-oa0-f53.google.com [209.85.219.53]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 3E7FEE044C for ; Mon, 17 Dec 2012 09:09:29 +0000 (UTC) Received: by mail-oa0-f53.google.com with SMTP id j6so5670198oag.40 for ; Mon, 17 Dec 2012 01:09:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=+I+KncNnM7HsUnw2bfbJ5HJJJMzBwgT7XulgdvsP5Bo=; b=A4AZ3iEetTnZ21oLS2z92Ho+dEB95SR6euubLvE8+9FuIgdGrZo4sRqbIF62JZa2tu N76Awhq7C8vdmwwI8zxvEEiifzNmtgxoZjerhDws2mF23ptopz7TIvms305WdBiya7Ae VuyBDs/inofH8qqs+ATnMVs7/NS4kESz6Y9TC/pgtrhRLXksd7XYGkIJT9mLBzPIqB0D YkcEkAn3WkNOfulqC8k0b8FaTwHlsVLCdlRhoJjC9gZGWD2etrRoFg0bquiIJidVbjFu Dsf0kSgfUm36VQZXHNDHuLrmZ9NMgYX+1lvt5nUzkeEqv1VZtpwbba0/i37ALtP1NXhe 008g== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.60.10.133 with SMTP id i5mr10728068oeb.24.1355735368372; Mon, 17 Dec 2012 01:09:28 -0800 (PST) Received: by 10.76.20.243 with HTTP; Mon, 17 Dec 2012 01:09:28 -0800 (PST) In-Reply-To: References: <2736930.yacMY2ChLQ@eve> <3746768.pcaWKEa8bt@localhost> <2349232.AYnSBWEt4m@eve> Date: Mon, 17 Dec 2012 04:09:28 -0500 Message-ID: Subject: Re: [gentoo-user] Dual or Quad CPU complications? From: Michael Mol To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: 5255f95e-ceed-4494-a67d-d94fd5e03257 X-Archives-Hash: dcfa3af61470d1c33b72aa8d9cd6e222 Something _really_ weird happened to your quoting; you quoted my email, but your email client said you wrote it. On Mon, Dec 17, 2012 at 2:00 AM, J. Roeleveld wrote: >> On Sun, Dec 16, 2012 at 10:39 AM, J. Roeleveld wrote: ^-- weird --^ >>> On Sunday, December 16, 2012 01:52:46 PM Volker Armin Hemmann wrote: >>>> Am Samstag, 15. Dezember 2012, 20:57:24 schrieb J. Roeleveld: >>>> > Even on a system with only 2 sockets, it can be useful to have NUMA >>>> > available. >>>> >>>> or not, because it costs you performance. >>> >>> When does it cost performance? >>> In all situations? >> >> It adds some additional logic to memory allocation (put an allocation >> near the process that uses it) and to process scheduling (keep the >> process near its memory, but bump it to a more distant idle core if >> necessary). > > That's the way it's supposed to work, yes :) > >> In all honestly, it's not a performance loss you're likely to notice, >> unless you're so in need of squeezing out every spare cycle that you >> most definitely _have_ hardware where there are disconnected memory >> banks. I'm not convinced it's even measurable for us mundanes and our >> hardware. > > I don't think I would notice it either, but as the system I have supports > it, I want to use it. > And then I want to be certain it actually supports it correctly. > > The system I'm talking about is used for testing purposes. Running > multiple VMs. As far as I know, Xen has support for it, just need to > configure it properly. > And for this usecase, I think NUMA with only 2 physical CPUs should make a > positive difference. Don't get me wrong; I was arguing that it shouldn't hurt to have it enabled. :) -- :wq