Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271283AbUJVMbK (ORCPT ); Fri, 22 Oct 2004 08:31:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271276AbUJVM2N (ORCPT ); Fri, 22 Oct 2004 08:28:13 -0400 Received: from clock-tower.bc.nu ([81.2.110.250]:19679 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S271271AbUJVMZo (ORCPT ); Fri, 22 Oct 2004 08:25:44 -0400 Subject: Re: How is user space notified of CPU speed changes? From: Alan Cox To: Lee Revell Cc: Linux Kernel Mailing List , Robert Love In-Reply-To: <1098399709.4131.23.camel@krustophenia.net> References: <1098399709.4131.23.camel@krustophenia.net> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1098444170.19459.7.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Fri, 22 Oct 2004 12:23:02 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 902 Lines: 20 On Gwe, 2004-10-22 at 00:01, Lee Revell wrote: > This issue came up on the JACK (http://jackit.sf.net) mailing list. > Google was not helpful so I ask here. > > JACK needs to know the CPU speed, in order to calculate the DSP load > among other things. It used to be a valid assumption that you could > calculate it on startup and it would not change. No it did not. It has never been a safe assumption. Even my old PC110 does APM non-linux assisted shifts between 8 16 and 33Mhz. In addition there are boxes with dual CPU's and different multipliers - dual 300/450's were not uncommon. And thats before we even mention such things at hyped-threading. - 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/