Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965219AbWJKJUO (ORCPT ); Wed, 11 Oct 2006 05:20:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965218AbWJKJUO (ORCPT ); Wed, 11 Oct 2006 05:20:14 -0400 Received: from dsl027-180-168.sfo1.dsl.speakeasy.net ([216.27.180.168]:23435 "EHLO sunset.davemloft.net") by vger.kernel.org with ESMTP id S965216AbWJKJUM (ORCPT ); Wed, 11 Oct 2006 05:20:12 -0400 Date: Wed, 11 Oct 2006 02:20:15 -0700 (PDT) Message-Id: <20061011.022015.63051509.davem@davemloft.net> To: mst@mellanox.co.il Cc: shemminger@osdl.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, openib-general@openib.org, rolandd@cisco.com Subject: Re: Dropping NETIF_F_SG since no checksum feature. From: David Miller In-Reply-To: <20061011090504.GC2938@mellanox.co.il> References: <20061010.191547.83619974.davem@davemloft.net> <20061011090504.GC2938@mellanox.co.il> X-Mailer: Mew version 4.2 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 642 Lines: 14 From: "Michael S. Tsirkin" Date: Wed, 11 Oct 2006 11:05:04 +0200 > So, it seems that if I set NETIF_F_SG but clear NETIF_F_ALL_CSUM, > data will be copied over rather than sent directly. > So why does dev.c have to force set NETIF_F_SG to off then? Because it's more efficient to copy into a linear destination buffer of an SKB than page sub-chunks when doing checksum+copy. - 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/