Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261731AbTKMMEF (ORCPT ); Thu, 13 Nov 2003 07:04:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263913AbTKMMEF (ORCPT ); Thu, 13 Nov 2003 07:04:05 -0500 Received: from mail-04.iinet.net.au ([203.59.3.36]:36493 "HELO mail.iinet.net.au") by vger.kernel.org with SMTP id S261731AbTKMMEB (ORCPT ); Thu, 13 Nov 2003 07:04:01 -0500 Message-ID: <3FB3732A.4060604@cyberone.com.au> Date: Thu, 13 Nov 2003 23:03:54 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030827 Debian/1.4-3 X-Accept-Language: en MIME-Version: 1.0 To: Catalin BOIE CC: linux-kernel@vger.kernel.org Subject: Re: 2.6.0test9 + 2 * P IV Xeon 2.4GHz with HT + SATA + RAID1 = scheduler problems References: <3FB36E18.2030105@cyberone.com.au> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1843 Lines: 61 Catalin BOIE wrote: >>Hi, >> >Hi! > > >>Please capture a Ctrl + Scroll Lock dump when you get processes stuck in >>D state. >> >I will. > > >>>Also I suspect that scheduler doesn't pay special attention to virtual >>>(HT) processors. Is this true? >>> >>> >>This is correct. Are you seeing any problems with HT? I think Linus >> > >Do you think that disabling HT (how I do it? noht?) will make things works >better? I suspect that a process is scheduled on a virtual processor that >doesn't get much chances to execute something. I don't know. > I can't see an option to just disable HT with a quick grep. acpi=off should do it though. The virtual processors should get a roughly even amount of work done AFAIK. I don't think the P4 allows any sort of control over priorities. > >>was hoping the NUMA / SMP scheduler could be generalised a bit more >>so that HT would just fall into place. This might not happen before >>2.7, so the shared runqueue approach might be the next best thing >>(I like it). >> > >The problem with HT is the one that I describe here. From time to time a >process (mc, bash) is stuck for 2-6 seconds and then comes back. In test8 >this was more visible. > >Thank you very much, Nick! > Oh, so it is not any sort of disk IO work that is getting stuck? Then don't worry about getting the Ctrl Scroll Lock trace... OK, well yes turn HT off and see if that helps. One other thing which springs to mind is that there is some CPU scheduler code that increases timeslice grainularity as the CPU count increases. It seems a bit unlikely that this is your problem though. - 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/