Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756900AbXEXXXh (ORCPT ); Thu, 24 May 2007 19:23:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753198AbXEXXX2 (ORCPT ); Thu, 24 May 2007 19:23:28 -0400 Received: from omta03ps.mx.bigpond.com ([144.140.82.155]:35710 "EHLO omta03ps.mx.bigpond.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750751AbXEXXX1 (ORCPT ); Thu, 24 May 2007 19:23:27 -0400 Message-ID: <46561E67.3030207@bigpond.net.au> Date: Fri, 25 May 2007 09:23:19 +1000 From: Peter Williams User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: "Siddha, Suresh B" CC: Ingo Molnar , colpatch@us.ibm.com, Nick Piggin , Con Kolivas , Christoph Lameter , Dmitry Adamushko , Linux Kernel Subject: Re: [patch] CFS scheduler, -v12 References: <464A6698.3080400@bigpond.net.au> <20070516063625.GA9058@elte.hu> <464CE8FD.4070205@bigpond.net.au> <20070518071325.GB28702@elte.hu> <464DA61A.4040406@bigpond.net.au> <46523081.6050007@bigpond.net.au> <465275EF.8060905@bigpond.net.au> <4652DC03.60801@bigpond.net.au> <4655423E.6000202@bigpond.net.au> <20070524164538.GA13301@linux-os.sc.intel.com> In-Reply-To: <20070524164538.GA13301@linux-os.sc.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Authentication-Info: Submitted using SMTP AUTH PLAIN at oaamta03ps.mx.bigpond.com from [60.231.45.148] using ID pwil3058@bigpond.net.au at Thu, 24 May 2007 23:23:24 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3292 Lines: 94 Siddha, Suresh B wrote: > On Thu, May 24, 2007 at 12:43:58AM -0700, Peter Williams wrote: >> Peter Williams wrote: >>> The relevant code, find_busiest_group() and find_busiest_queue(), has a >>> lot of code that is ifdefed by CONFIG_SCHED_MC and CONFIG_SCHED_SMT and, >>> as these macros were defined in the kernels I was testing with, I built >>> a kernel with these macros undefined and reran my tests. The >>> problems/anomalies were not present in 10 consecutive tests on this new >>> kernel. Even better on the few occasions that a 3/1 split did occur it >>> was quickly corrected to 2/2 and top was reporting approx 49% of CPU for >>> all spinners throughout each of the ten tests. >>> >>> So all that is required now is an analysis of the code inside the ifdefs >>> to see why it is causing a problem. >> >> Further testing indicates that CONFIG_SCHED_MC is not implicated and >> it's CONFIG_SCHED_SMT that's causing the problem. This rules out the >> code in find_busiest_group() as it is common to both macros. >> >> I think this makes the scheduling domain parameter values the most >> likely cause of the problem. I'm not very familiar with this code so >> I've added those who've modified this code in the last year or >> so to the >> address of this e-mail. > > What platform is this? I remember you mentioned its a 2 cpu box. Is it > dual core or dual package or one with HT? It's a single CPU HT box i.e. 2 virtual CPUs. "cat /proc/cpuinfo" produces: processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 3 model name : Intel(R) Pentium(R) 4 CPU 3.20GHz stepping : 4 cpu MHz : 3201.145 cache size : 1024 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 1 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc pni monitor ds_cpl cid xtpr bogomips : 6403.97 clflush size : 64 processor : 1 vendor_id : GenuineIntel cpu family : 15 model : 3 model name : Intel(R) Pentium(R) 4 CPU 3.20GHz stepping : 4 cpu MHz : 3201.145 cache size : 1024 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 1 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc pni monitor ds_cpl cid xtpr bogomips : 6400.92 clflush size : 64 Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce - 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/