Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750773AbWCVF1z (ORCPT ); Wed, 22 Mar 2006 00:27:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750774AbWCVF1z (ORCPT ); Wed, 22 Mar 2006 00:27:55 -0500 Received: from mailout10.sul.t-online.com ([194.25.134.21]:6119 "EHLO mailout10.sul.t-online.com") by vger.kernel.org with ESMTP id S1750773AbWCVF1y (ORCPT ); Wed, 22 Mar 2006 00:27:54 -0500 Message-ID: <4420DE54.1020004@t-online.de> Date: Wed, 22 Mar 2006 06:19:16 +0100 From: Knut Petersen User-Agent: Mozilla/5.0 (X11; U; Linux i686; de-AT; rv:1.7.10) Gecko/20050726 X-Accept-Language: de, en MIME-Version: 1.0 To: Linus Torvalds CC: Dave Jones , Linux Kernel Mailing List , Andrew Morton Subject: Re: [BUG] wrong bogomips values with kernel 2.6.16 References: <441FFB28.5050609@t-online.de> In-Reply-To: X-Enigmail-Version: 0.86.0.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-ID: Xdfi34ZlweIz3Ctfpx1LPRbJjdq4VpfTIlLuWm3muIMp7a9L3mr0g-@t-dialin.net X-TOI-MSGID: 62f6d9d0-f58b-4942-8d02-9d0cc57c3ae6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1773 Lines: 57 Linus Torvalds schrieb: >That sounds correct. On x86, BogoMips these days is just a measure of how >fast the timestamp counter goes (multiplied by two for totally bogus >reasons), and a Pentium-M should have a fixed-frequency TSC that ticks at >the highest possible frequency of the CPU, regardless of what the real >frequency is. > > > Pentium 4 and Xeon model 3 and above increment the time stamp counter at a constant rate independent of the current cpu frequency. All Pentium M, Xeon up to model 2 and the P6 family increment with every internal processor cycle. This behaviour is documented in chapter 18.8 of IA-32 Intel? Architecture Software Developer?s Manual, Volume 3B: System Programming Guide, Part 2, Order Number: 253669-018, January 2006. Because of your false assumption of a fixed-frequency TSC, your conclusions are false too. Scaling of the bogomips values should really happen, but the start value is wrong. For 800 MHz there should be a bogomips value of about 1598, for 1867 MHz a value of about 3730. You asked for a full /proc/cpuinfo, here it is ... processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 13 model name : Intel(R) Pentium(R) M processor 1.86GHz stepping : 8 cpu MHz : 800.000 cache size : 2048 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2 bogomips : 3730.27 cu, Knut - 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/