Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 28 Aug 2002 16:39:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 28 Aug 2002 16:39:31 -0400 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:47112 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Wed, 28 Aug 2002 16:39:15 -0400 Date: Wed, 28 Aug 2002 13:46:11 -0700 (PDT) From: Linus Torvalds To: "Grover, Andrew" cc: Dominik Brodowski , , Subject: RE: [PATCH][2.5.32] CPU frequency and voltage scaling (0/4) In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1127 Lines: 30 On Wed, 28 Aug 2002, Grover, Andrew wrote: > > Well TMTA CPUs would seem to be easy, because all this is done behind the > OS's back, right? Yes. However, I certainly wouldn't mind having the same interfaces as everybody else to set things like "aggressive" vs "powersave". Transmeta does all the actual _work_ behind the OS's back, but you can still tell the CPU what policy to take, and what frequency limits to use. > Let's talk about CPUs in which the OS has to control processor performance. > The way I see it, there are a bunch of inputs that are going to determine > CPU speed & voltage: user preference, workload, and thermals. Absolutely. > Any workload analysis has to be in the kernel. ...with user mode input (ie user mode can know a lot of high-level stuff that the kernel _doesn't_ know). So the kernel does potentially need user input on policy. Linus - 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/