Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756712AbYCTQDb (ORCPT ); Thu, 20 Mar 2008 12:03:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753520AbYCTQDX (ORCPT ); Thu, 20 Mar 2008 12:03:23 -0400 Received: from mx1.redhat.com ([66.187.233.31]:43887 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752866AbYCTQDX (ORCPT ); Thu, 20 Mar 2008 12:03:23 -0400 Subject: CPU siblings From: Jon Masters To: linux-kernel@vger.kernel.org Cc: Jeff Burke Content-Type: text/plain Organization: Red Hat, Inc. Date: Thu, 20 Mar 2008 12:03:16 -0400 Message-Id: <1206028996.5225.6.camel@jcmlaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.8.0 (2.8.0-33.el5) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 940 Lines: 23 Yo, Myself and a colleague were just discussing the output of /proc/cpuinfo, specifically the CPU siblings field. He pointed out/we think that this historically was supposed to be number of HT siblings for a given CPU. The actual value of that field comes from the Hamming Weight (number of set bits) of the per_cpu cpu_core_map variable, which supposedly is "representing HT and core siblings of each logical CPU", i.e. both HT siblings and additional cores within the same CPU package. Does this mean that "siblings" needs renaming? (doesn't it come originally from "HT siblings"? or is it supposed to be both?). More importantly, what's the correct way to determine number of HTs? Jon. -- 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/