Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933175AbXJLQiq (ORCPT ); Fri, 12 Oct 2007 12:38:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755563AbXJLQif (ORCPT ); Fri, 12 Oct 2007 12:38:35 -0400 Received: from mga03.intel.com ([143.182.124.21]:8890 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754941AbXJLQie (ORCPT ); Fri, 12 Oct 2007 12:38:34 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.21,267,1188802800"; d="scan'208";a="297473366" Message-ID: <470FA243.6030908@intel.com> Date: Fri, 12 Oct 2007 09:35:15 -0700 From: "Kok, Auke" User-Agent: Thunderbird 2.0.0.6 (X11/20070911) MIME-Version: 1.0 To: 7eggert@gmx.de CC: Kok@imap.glb.intel.com, prasad@linux.vnet.ibm.com, Lennart Sorensen , Pavel Machek , Arjan van de Ven , kernel list Subject: Re: gigabit ethernet power consumption References: <9c8XH-7gs-13@gated-at.bofh.it> <9c9qN-7Rn-19@gated-at.bofh.it> <9cs0n-3Dc-9@gated-at.bofh.it> <9csjH-43E-33@gated-at.bofh.it> <9d4yC-5hT-7@gated-at.bofh.it> <9d7ZJ-2mI-11@gated-at.bofh.it> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 12 Oct 2007 16:35:35.0536 (UTC) FILETIME=[EA286F00:01C80CED] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1546 Lines: 34 Bodo Eggert wrote: > Kok, Auke wrote: >> K.Prasad wrote: > >>> Without the side-effect of experiencing a link-flap when switching to a >>> lower-speed (with its toll in terms of down-time for auto-negotiation, >>> STP, etc), the Interrupt Moderation Algorithm dynamically adjusts the >>> number of interrupts based on traffic - and presumably consume less >>> power. For an "Optimise for Power" kind of profile - the driver can be >>> loaded with a higher throttle rate during boot-time. >> We're changing this to be run-time adjustable in newer drivers. >> >> However, the power consumed by your nic staying in gigabit mode is much >> greater in the long run then what you can save by trying to scrounge for >> milliwatts reducing interrupts generated by the nic. By default it already >> moderates them somewhat. Practically this feature is really not useful for >> powersaving, it just won't add up to actual benefits in a real life situtation >> I think. > > Just a thought: > How much power does a non-connected NIC consume, and can you save power > by forcing 10 MBit until a link is detected (doubling negotiation time)? no, the PHY consumes a minimal amount of energy when not connected, regardless of whether it is advertising 10, 100 or 1000mbit. Cheers, Auke - 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/