Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262151AbTFJWDF (ORCPT ); Tue, 10 Jun 2003 18:03:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262431AbTFJWDF (ORCPT ); Tue, 10 Jun 2003 18:03:05 -0400 Received: from meryl.it.uu.se ([130.238.12.42]:62345 "EHLO meryl.it.uu.se") by vger.kernel.org with ESMTP id S262151AbTFJWC5 (ORCPT ); Tue, 10 Jun 2003 18:02:57 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16102.22713.50999.54138@gargle.gargle.HOWL> Date: Wed, 11 Jun 2003 00:16:25 +0200 From: mikpe@csd.uu.se To: Steven Cole Cc: Alan Cox , Samuel Flory , John Appleby , xyko_ig@ig.com.br, Linux Kernel Mailing List Subject: Re: Wrong number of cpus detected/reported In-Reply-To: <1055281927.2269.47.camel@spc9.esa.lanl.gov> References: <434747C01D5AC443809D5FC540501131569E@bobcat.unickz.com> <3EE64161.5010102@rackable.com> <1055279041.2270.42.camel@spc9.esa.lanl.gov> <1055280955.32661.35.camel@dhcp22.swansea.linux.org.uk> <1055281927.2269.47.camel@spc9.esa.lanl.gov> X-Mailer: VM 6.90 under Emacs 20.7.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 962 Lines: 22 Steven Cole writes: > On Tue, 2003-06-10 at 15:35, Alan Cox wrote: > > > wp : yes > > > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm > > > bogomips : 2798.38 > > > > > > See that ht flag near the end? > > > > The ht flag means the ht facilities (mtrr etc) are present, doesnt mean > > HT necessarily is > > Is there a reliable method, apart from knowing 'a priori' the mapping > from CPU models and stepping to hyperthreading capability? Yes. Execute cpuid with eax=1 on each CPU. ebx describes among other things the number of threads and which thread you're on. If you ever find yourself on a non-zero thread, you have HT. - 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/