From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266173AbUHZAtM (ORCPT ); Wed, 25 Aug 2004 20:49:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266512AbUHZAtM (ORCPT ); Wed, 25 Aug 2004 20:49:12 -0400 Received: from delerium.kernelslacker.org ([81.187.208.145]:131 "EHLO delerium.codemonkey.org.uk") by vger.kernel.org with ESMTP id S266173AbUHZAtL (ORCPT ); Wed, 25 Aug 2004 20:49:11 -0400 Date: Thu, 26 Aug 2004 01:48:57 +0100 From: Dave Jones To: Dan Hollis Cc: linux-kernel@vger.kernel.org Subject: Re: bizarre 2.6.8.1 /sys permissions Message-ID: <20040826004857.GA5583@redhat.com> Mail-Followup-To: Dave Jones , Dan Hollis , linux-kernel@vger.kernel.org References: <20040825221814.GA20283@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 25, 2004 at 04:31:50PM -0700, Dan Hollis wrote: > > > $ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq > > > cat: /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq: Permission denied > > Reading this file causes reads from hardware on some cpufreq drivers. > > This can be a slow operation, so a user could degrade system performance > > for everyone else by repeatedly cat'ing it. > > any reason why cpuinfo_cur_freq cant read cpu_khz ? cpufreq_cur_freq will be one of scaling_available_frequencies. These are usually a value such as 1300MHz, where cpu_mhz is a 'measured' value and will look something like 1303.852 the values cpufreq uses are the values either returned by the hardware as its settable states, or from BIOS tables defining those states. > or rather, is there any reason why cpuinfo_cur_freq and /proc/cpuinfo > should legitimately differ? They aren't identical, and serve different purposes. Dave