From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: Checksum offload queries Date: Wed, 9 Dec 2015 23:44:45 +0100 Message-ID: <20151209224445.GI11201@pox.localdomain> References: <5665A848.9010001@solarflare.com> <20151207.143848.2158761076110518741.davem@davemloft.net> <5666EC4B.40800@solarflare.com> <20151208.120654.2127200076257822677.davem@davemloft.net> <56681B18.3030200@solarflare.com> <566864C0.6020204@solarflare.com> <20151209222153.GE11201@pox.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Edward Cree , Linux Kernel Network Developers , David Miller To: Tom Herbert Return-path: Received: from mail-wm0-f47.google.com ([74.125.82.47]:36603 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753835AbbLIWor (ORCPT ); Wed, 9 Dec 2015 17:44:47 -0500 Received: by mail-wm0-f47.google.com with SMTP id w144so1213538wmw.1 for ; Wed, 09 Dec 2015 14:44:47 -0800 (PST) Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 12/09/15 at 02:42pm, Tom Herbert wrote: > csum_start and csum_offset together occupy 32 bits. As demonstrated in > VXLAN RCO we can compress csum_start/csum_offset down to 8 bits which > means if necessary we could get up to four pairs in an sk_buff without > increasing its size. If you need more that four checksums to be > offloaded in single packet then I doubt getting checksum offload to > work is going to be your biggest problem. Fair point. I wouldn't suggest even creating it without huge demand first. There should be as many incentives as possible to move or stay away from such horrible architectures.