From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755412Ab2JKHT4 (ORCPT ); Thu, 11 Oct 2012 03:19:56 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:52700 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752147Ab2JKHTx convert rfc822-to-8bit (ORCPT ); Thu, 11 Oct 2012 03:19:53 -0400 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Subject: Re: Meaningless load? From: Simon Klinkert In-Reply-To: <1349886164.1279.20.camel@twins> Date: Thu, 11 Oct 2012 09:19:49 +0200 Cc: LKML , mingo@redhat.com, Trond.Myklebust@netapp.com Content-Transfer-Encoding: 8BIT Message-Id: <8CCB73B0-34AD-47E2-9379-DB6F02DB35F5@gmail.com> References: <98F2F644-D531-42FE-B080-9561142D71C8@gmail.com> <1349886164.1279.20.camel@twins> To: Peter Zijlstra , Mike Galbraith X-Mailer: Apple Mail (2.1499) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.10.2012, at 18:22, Peter Zijlstra wrote: > On Wed, 2012-10-10 at 17:44 +0200, Simon Klinkert wrote: >> I'm just wondering if the 'load' is really meaningful in this >> scenario. The machine is the whole time fully responsive and looks >> fine to me but maybe I didn't understand correctly what the load >> should mean. Is there any sensible interpretation of the load? > > I'll leave meaningful aside, but uninterruptible (D state) is part of > how the load thing is defined, so your 500 result is correct. Yes, the calculation of the load is correct but I still don't know how I should interpret the load… On 11.10.2012, at 06:02, Mike Galbraith wrote: > Makes perfect sense to me. Work _is_ stack this high. We don't and > can't know whether the mountain is made of popcorn balls or boulders. That's the point. Afaik the D state never represents 'work'. These processes are waiting for something. Let's say we have 10,000 processes in the D state (and thus a load of ~10,000) doing nothing. What should the load tell me? The machine is under fire? There is nothing to do? There might be something to do but the machine doesn't know? Simon