From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765461AbXLNKpV (ORCPT ); Fri, 14 Dec 2007 05:45:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757955AbXLNKom (ORCPT ); Fri, 14 Dec 2007 05:44:42 -0500 Received: from [194.117.236.238] ([194.117.236.238]:45845 "EHLO heracles.linux360.ro" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1757285AbXLNKol (ORCPT ); Fri, 14 Dec 2007 05:44:41 -0500 Date: Fri, 14 Dec 2007 15:41:06 +0200 From: Eduard-Gabriel Munteanu To: Andi Kleen Cc: LKML , Thomas Gleixner Subject: Re: [PATCH] Option to disable AMD C1E (allows dynticks to work) Message-ID: <20071214154106.4f0b2d8c@linux360.ro> In-Reply-To: <20071214101720.GA10981@one.firstfloor.org> References: <20071214004442.5f9eba88@linux360.ro> <20071214143941.2c7dcfb4@linux360.ro> <20071214101720.GA10981@one.firstfloor.org> X-Mailer: Claws Mail 3.0.2 (GTK+ 2.10.14; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Dec 2007 11:17:21 +0100 Andi Kleen wrote: > >so do whatever is necessary to enable dynticks. > > dynticks' main purpose is to save power, but C1e saves more power. > Disabling C1e for dynticks would be a fairly useless default > trade off. I see. Also, AMD specs say that either higher C-states are enabled, or C1E, but not both at the same time. So if the BIOS doesn't offer an option to disable C1E, it can't provide _CST or P_LVL* ACPI objects for higher C-states. Dynticks also provides lower latencies as far as I know. I think this workaround should be merged, even if as a non-default config option. I'll resubmit a patch if you agree. (By the way, sorry for messing up the "Cc:" fields in the previous message.)