From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16420 invoked by alias); 7 Jun 2011 08:55:54 -0000 Received: (qmail 16401 invoked by uid 22791); 7 Jun 2011 08:55:53 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from tirion.supremecenter202.com (HELO tirion.supremecenter202.com) (209.25.195.243) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 07 Jun 2011 08:55:33 +0000 Received: from c-98d9e155.355-1-64736c10.cust.bredbandsbolaget.se ([85.225.217.152]:51082 helo=[192.168.0.116]) by tirion.supremecenter202.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from ) id 1QTs4T-0008Oc-9M; Tue, 07 Jun 2011 08:55:33 +0000 Message-ID: <4DEDE781.5040108@siva.com.mk> Date: Tue, 07 Jun 2011 08:55:00 -0000 From: Ilija Kocho User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110424 Lightning/1.0b2 Thunderbird/3.1.10 ThunderBrowse/3.3.5 MIME-Version: 1.0 To: ecos-discuss@ecos.sourceware.org, eCos developers Subject: Re: [ECOS] Re: How to use IP/UDP/TCP checksum offload HW? References: <1478E21E-D36A-4451-9F69-0042CBF57E91@netic.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact ecos-devel-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: ecos-devel-owner@ecos.sourceware.org X-SW-Source: 2011-06/txt/msg00001.txt.bz2 On 07.06.2011 04:18, Laurie Gellatly wrote: > > On 07/06/2011, at 10:57 AM, Grant Edwards wrote: > >> On 2011-06-07, Laurie Gellatly wrote: >> >>> I tried to enable this before without success. >> Ah yes, I saw your (unanswered) post from a few years back asking >> about this. I was hoping there had been some progress since then. >> >>> I agree that its a waste of processor time when it can be performed >>> in hardware. >> The last time I did some profiling, IP checksum calculation was a >> pretty significant bottleneck for TCP throughput. Back in the NetBSD >> stack days, I got about a 20% improvement in throughput by writing my >> own assembly-language IP checksum routine for ARM7. The FreeBSD C >> implementation and more recent versions of gcc do almost as well as >> hand-tuned assembly, but it's still a big percentage of CPU usage in >> TCP communications -- and it will be even worse now that I have a chip >> that does scatter-gather DMA. A part for US $4 that has IP checksum >> offloading and scatter-gather DMA. Back when I was a new grad... >> >>> Must we look at the latest BSD code to see how to implement this? >> Maybe. Or there might be a simpler way to do it. I would guess that >> the current FreeBSD has an API to configure this on a per-interface >> basis at run-time. >> >> If we can assume that there is only one external interface, then we >> don't need any API or runtime checks, just a few strategic #if/#endif >> pairs and some CDL to control them. >> >> -- >> Grant >> >> >> -- >> Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos >> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss >> > So how do we progress this? > Should we offline exchange the mods we've each tried (code and CDL)? I am going to need the same soon only with lwIP. Recent on-chip Ethernet controllers provide for some IP processing so IMO we should address this issue generally. Is there place for some community project? Ilija.