Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751375AbWEIEgs (ORCPT ); Tue, 9 May 2006 00:36:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751377AbWEIEgs (ORCPT ); Tue, 9 May 2006 00:36:48 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:61374 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1751375AbWEIEgs (ORCPT ); Tue, 9 May 2006 00:36:48 -0400 Subject: Re: High load average on disk I/O on 2.6.17-rc3 From: Arjan van de Ven To: Nick Piggin Cc: Erik Mouw , "Martin J. Bligh" , Andrew Morton , Jason Schoonover , linux-kernel@vger.kernel.org In-Reply-To: <445FF714.4050803@yahoo.com.au> References: <200605051010.19725.jasons@pioneer-pra.com> <20060507095039.089ad37c.akpm@osdl.org> <445F548A.703@mbligh.org> <1147100149.2888.37.camel@laptopd505.fenrus.org> <20060508152255.GF1875@harddisk-recovery.com> <1147102290.2888.41.camel@laptopd505.fenrus.org> <445FF714.4050803@yahoo.com.au> Content-Type: text/plain Date: Tue, 09 May 2006 06:36:39 +0200 Message-Id: <1147149399.3198.10.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1255 Lines: 33 On Tue, 2006-05-09 at 11:57 +1000, Nick Piggin wrote: > Arjan van de Ven wrote: > > >>... except that any kernel < 2.6 didn't account tasks waiting for disk > >>IO. > >> > > > >they did. It was "D" state, which counted into load average. > > > > Perhaps kernel threads in D state should not contribute toward load avg that would be a change from, well... a LONG time The question is what "load" means; if you want to change that... then there are even better metrics possible. Like "number of processes wanting to run + number of busy spindles + number of busy nics + number of VM zones that are below the problem watermark" (where "busy" means "queue full") or 50 million other definitions. If we're going to change the meaning, we might as well give it a "real" meaning. (And even then it is NOT a good measure for determining if the machine can perform more work, the graph I put in a previous mail is very real, and in practice it seems the saturation line is easily 4x or 5x of the "linear" point) - 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/