Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 24 Oct 2002 18:55:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 24 Oct 2002 18:55:41 -0400 Received: from bozo.vmware.com ([65.113.40.131]:48909 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id ; Thu, 24 Oct 2002 18:55:39 -0400 Date: Thu, 24 Oct 2002 16:02:29 -0700 From: chrisl@vmware.com To: linux-kernel@vger.kernel.org Subject: How to get number of physical CPU in linux from user space? Message-ID: <20021024230229.GA1841@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 793 Lines: 25 It seems that /proc/cpuinfo will return the number of logical CPU. If the machine has Intel Hyper-Thread enabled, that number is bigger than physical CPU number. Usually twice as big. My question is, what is the reliable way for user space program to detect the number of physical CPU in the current machine? If in it is in the kernel, I can read from cpu_sibling_map[] or phys_cpu_id[]. But it seems not easy read that from user space. Of course I can do "gdb /proc/kcore" to get them. But is there any better way? Thanks in advance. Chris - 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/