Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932411AbWEHQCO (ORCPT ); Mon, 8 May 2006 12:02:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932409AbWEHQCN (ORCPT ); Mon, 8 May 2006 12:02:13 -0400 Received: from dvhart.com ([64.146.134.43]:57057 "EHLO dvhart.com") by vger.kernel.org with ESMTP id S932411AbWEHQCM (ORCPT ); Mon, 8 May 2006 12:02:12 -0400 Message-ID: <445F6B7E.8030804@mbligh.org> Date: Mon, 08 May 2006 09:02:06 -0700 From: "Martin J. Bligh" User-Agent: Mozilla Thunderbird 1.0.7 (X11/20051013) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Erik Mouw Cc: Arjan van de Ven , Andrew Morton , Jason Schoonover , linux-kernel@vger.kernel.org Subject: Re: High load average on disk I/O on 2.6.17-rc3 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> <20060508154217.GH1875@harddisk-recovery.com> In-Reply-To: <20060508154217.GH1875@harddisk-recovery.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 50 Erik Mouw wrote: > On Mon, May 08, 2006 at 05:31:29PM +0200, Arjan van de Ven wrote: > >>On Mon, 2006-05-08 at 17:22 +0200, Erik Mouw 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. > > > They did not or at least to a much lesser extent. That's the reason why > ZenIV.linux.org.uk had a mail DoS during the last FC release and why we > see load average questions on lkml. > > I've seen it on our servers as well: when using 2.4 and doing 50 MB/s > to disk (through NFS), the load just was slightly above 0. When we > switched the servers to 2.6 it went to ~16 for the same disk usage. Looks like both count it, or something stranger is going on. 2.6.16: static unsigned long count_active_tasks(void) { return (nr_running() + nr_uninterruptible()) * FIXED_1; } 2.4.0: static unsigned long count_active_tasks(void) { struct task_struct *p; unsigned long nr = 0; read_lock(&tasklist_lock); for_each_task(p) { if ((p->state == TASK_RUNNING || (p->state & TASK_UNINTERRUPTIBLE))) nr += FIXED_1; } read_unlock(&tasklist_lock); return nr; } - 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/