From owner-freebsd-net@FreeBSD.ORG Mon Jan 7 21:41:24 2013 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 7F668A13 for ; Mon, 7 Jan 2013 21:41:24 +0000 (UTC) (envelope-from barney_cordoba@yahoo.com) Received: from nm12-vm1.bullet.mail.ne1.yahoo.com (nm12-vm1.bullet.mail.ne1.yahoo.com [98.138.91.41]) by mx1.freebsd.org (Postfix) with ESMTP id 3DB3487A for ; Mon, 7 Jan 2013 21:41:24 +0000 (UTC) Received: from [98.138.90.51] by nm12.bullet.mail.ne1.yahoo.com with NNFMP; 07 Jan 2013 21:41:17 -0000 Received: from [98.138.89.246] by tm4.bullet.mail.ne1.yahoo.com with NNFMP; 07 Jan 2013 21:41:17 -0000 Received: from [127.0.0.1] by omp1060.mail.ne1.yahoo.com with NNFMP; 07 Jan 2013 21:41:17 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 103079.12163.bm@omp1060.mail.ne1.yahoo.com Received: (qmail 65278 invoked by uid 60001); 7 Jan 2013 21:41:16 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1357594876; bh=cdmjs445P9/UdRk/lJW67EBxZCYAz/JSDNRAzox16wk=; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:Message-ID:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=OB0CASrjNEBpYqZDT+S6kdaAccxYr/Pg+3ETm/2FPoBHQlKyuHGPAkbeYOjt/7LN2KiSwqGgWzfQwMVGr5nd1xfxkeR95Nib+IeUMnsgBw901O8SJECjngENyTdtlAZHzCLM2R0hHruQ127btNXGRjBjnYCWX8gy0Oq4itCSqoQ= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:Message-ID:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=W9wRXfjYQzNM2pYuQlxyxtHW03xy8jLynUH+k1fg6clWKUHH1xzwBWI1lNq5s+YZTVD6CtIAILDZddTvo2J3xkF/DVb9v66SQusmB5ADRIP1cJ6mS+9FRfoQRt0hBj7r3AA9JhE05jRM1xfBklWCBJX971EdUe6BPoHucUJmbdg=; X-YMail-OSG: bnYM04EVM1nH36QQLzAAcwe27UYbxNJXLypDRkMgorMVHnj t3fiOfQfHlapic8VmMmsSl5xi52LfhXZc9_r4tVk_o9.aAeNdf_ToA9L7pHE BWotQNFmHOsx19VFJ4Q.WAWCQ2C0HlM9Jdr4kyQKKLlaGMqrfWdK2eDn0G3z NyRHMhLyTa7aYnK3SGwxNksL7WyWWQ_ndrKVt7gEEeiOSK1R3VCdph1jqxJI w.vrOkj.6qraVasqVmuYv99XKS5KgfVBZCnDbTxh4S_3Lrofc4aJVqrWayWY WRB_zboYXV6K4LqPIBVYsAwEX00Rf0DYMqBr9cwJTnikJoj_KDAlUgkEhbOI 9qhsTfjkgh56r08kVavKec5I1CCaIIxD2N3ikqCFIpL3WcdwyGoe3heqBabX ZQMwrZ4F1bR7xDeTWiGc1_64WFdVABqAWDYjHLAog5Zj5J2RZ_G1BBjXYo5y pr6QigRaElF7Go1C9G8aZCRMObb9c35fry9owtF0qVVkj8XuZJKstzLVUuTa Ysys55sw3cK019sKhQUkvJvbOj9GaRw-- Received: from [174.48.128.27] by web121603.mail.ne1.yahoo.com via HTTP; Mon, 07 Jan 2013 13:41:16 PST X-Rocket-MIMEInfo: 001.001, DQoNCi0tLSBPbiBNb24sIDEvNy8xMywgV2lsbGVtIEphbiBXaXRoYWdlbiA8d2p3QGRpZ2l3YXJlLm5sPiB3cm90ZToNCg0KPiBGcm9tOiBXaWxsZW0gSmFuIFdpdGhhZ2VuIDx3andAZGlnaXdhcmUubmw.DQo.IFN1YmplY3Q6IFJlOiBrZXJuLzE3NDg1MTogW2J4ZV0gW3BhdGNoXSBVRFAgY2hlY2tzdW0gb2ZmbG9hZCBpcyB3cm9uZyBpbiBieGUgZHJpdmVyDQo.IFRvOiAiQmFybmV5IENvcmRvYmEiIDxiYXJuZXlfY29yZG9iYUB5YWhvby5jb20.DQo.IENjOiAiR2FycmV0dCBDb29wZXIiIDx5YW5lZ29taUABMAEBAQE- X-Mailer: YahooMailClassic/15.1.2 YahooMailWebService/0.8.130.494 Message-ID: <1357594876.61921.YahooMailClassic@web121603.mail.ne1.yahoo.com> Date: Mon, 7 Jan 2013 13:41:16 -0800 (PST) From: Barney Cordoba Subject: Re: kern/174851: [bxe] [patch] UDP checksum offload is wrong in bxe driver To: Willem Jan Withagen In-Reply-To: <50EA8558.4010600@digiware.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Garrett Cooper , freebsd-net@freebsd.org, Adrian Chadd , David Christensen , linimon@freebsd.org X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jan 2013 21:41:24 -0000 --- On Mon, 1/7/13, Willem Jan Withagen wrote: > From: Willem Jan Withagen > Subject: Re: kern/174851: [bxe] [patch] UDP checksum offload is wrong in = bxe driver > To: "Barney Cordoba" > Cc: "Garrett Cooper" , freebsd-net@freebsd.org, "Adri= an Chadd" , "David Christensen" , = linimon@freebsd.org > Date: Monday, January 7, 2013, 3:20 AM > On 2013-01-05 16:17, Barney Cordoba > wrote: > >=20 > >=20 > > --- On Fri, 1/4/13, Willem Jan Withagen > wrote: > >=20 > >> From: Willem Jan Withagen > >> Subject: Re: kern/174851: [bxe] [patch] UDP > checksum offload is wrong in bxe driver > >> To: "Barney Cordoba" > >> Cc: "Garrett Cooper" , > freebsd-net@freebsd.org, > "Adrian Chadd" , > "David Christensen" , > linimon@freebsd.org > >> Date: Friday, January 4, 2013, 9:41 AM > >> On 2013-01-01 0:04, Barney Cordoba > >> wrote: > >> > >>> The statement above "assumes" that there is a > benefit. > >> voIP packets=20 > >>> are short, so the benefit of offloading is > reduced. > >> There is some > >>> delay added by the hardware, and there are cpu > cycles > >> used in managing > >>> the offload code. So those operations not only > muddy > >> the code, > >>> but they may not be faster than simply doing > the > >> checksum on a much, much > >>> faster cpu. > >> > >> Forgoing all the discussions on performance and > possible > >> penalties in > >> drivers..... > >> > >> I think there is a large set of UDP streams (and > growing) > >> that do use > >> larger packets. > >> > >> The video streaming we did used a size of > header(14)+7*188, > >> which is the > >> max number of MPEG packet to fit into anything with > an MTU > >> < 1500. > >> > >> Receiving those on small embedded devices which can > do HW > >> check-summing > >> is very beneficial there. > >> On the large servers we would generate up to 5Gbit > of > >> outgoing streams. > >> I'm sure that offloading UDP checks would be an > advantage as > >> well. > >> (They did run mainly Linux, but FreeBSD would also > work) > >> > >> Unfortunately most of the infrastructure has been > taken > >> down, so it is > >> no longer possible to verify any of the > assumptions. > >> > >> --WjW > >=20 > > If you haven't benchmarked it, then you're just > guessing. That's my point. > >=20 > > Its like SMP in freeBSD 4. People bought big, honking > machines and the > > big expensive machines were slower than a single core > system at less than > > half the price. Just because something sounds better > doesn't mean that it is better. >=20 > I completely agree.... >=20 > Dutch proverb goes: > =A0=A0=A0 "To measure is to know" > Which was the subtitle of my graduation report, and my > professional > motto when working as a systems-architect.... >=20 > That's why it is sad that the system is no longer up and > running, > because a 0-order check would be no more that 1 ifconfig > would have made > a difference. >=20 > But that is all water under the bridge. >=20 > --WjW You can't really benchmark on a live network; you need a control. It's easy enough to generate controlled UDP streams. And of course every NIC would be a new deal. I'm sure that UDP offload is a checklist feature and not something that the intels and broadcoms of the world do a lot of=20 performance testing for. BC