Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030774AbWJKDdv (ORCPT ); Tue, 10 Oct 2006 23:33:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030769AbWJKDdu (ORCPT ); Tue, 10 Oct 2006 23:33:50 -0400 Received: from sj-iport-6.cisco.com ([171.71.176.117]:61786 "EHLO sj-iport-6.cisco.com") by vger.kernel.org with ESMTP id S1030499AbWJKDdt (ORCPT ); Tue, 10 Oct 2006 23:33:49 -0400 To: "Michael S. Tsirkin" Cc: Stephen Hemminger , Linux Kernel Mailing List , netdev@vger.kernel.org, openib-general@openib.org, Roland Dreier , "David S. Miller" Subject: Re: Dropping NETIF_F_SG since no checksum feature. X-Message-Flag: Warning: May contain useful information References: <20061011002656.GB30093@mellanox.co.il> From: Roland Dreier Date: Tue, 10 Oct 2006 20:33:46 -0700 In-Reply-To: <20061011002656.GB30093@mellanox.co.il> (Michael S. Tsirkin's message of "Wed, 11 Oct 2006 02:26:56 +0200") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) XEmacs/21.4.18 (linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 11 Oct 2006 03:33:48.0404 (UTC) FILETIME=[10239B40:01C6ECE6] Authentication-Results: sj-dkim-5.cisco.com; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com verified; ); Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 605 Lines: 14 Michael> My guess was, an extra pass over data is likely to be Michael> expensive - dirtying the cache if nothing else. But I do Michael> plan to measure that, and see. I don't get it -- where's the extra pass? If you can't compute the checksum on the NIC then you have to compute sometime it on the CPU before passing the data to the NIC. - R. - 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/