From owner-freebsd-current@FreeBSD.ORG Fri Jul 4 10:25:39 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 6B924934 for ; Fri, 4 Jul 2014 10:25:39 +0000 (UTC) Received: from mail-lb0-x22b.google.com (mail-lb0-x22b.google.com [IPv6:2a00:1450:4010:c04::22b]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id D4CE32964 for ; Fri, 4 Jul 2014 10:25:38 +0000 (UTC) Received: by mail-lb0-f171.google.com with SMTP id s7so1035161lbd.30 for ; Fri, 04 Jul 2014 03:25:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=U+Bl0pts6RVIOIINw1VoI7mjZGwuqm54UCfx96ZqS30=; b=uGGjvXahCRNo/0/80Bo73/kg8+k0R21yVhBm1bxHh18kfQrX0TCStvjeJetYDcOQr8 SHeTTs4IPms69bULcPbw1M9q0uiopIdvaxG6KeLdqSFLD6HH50NRqKdD3luMaJiZtcpk x/sl+xfNBZWDHAbFRdL+lF9/wpbeb0V7jqEz+/n4OX09egI9iNLdj8D9Mh6OlIccSk9q 6SogTt+TlbNYNJ1LiEHu0Dpm8ihnz3SJimtfjuiNsceuXkxcV3XBBYqPu85QL9bGcPDc DdUiyGLCWFabG4s6wqOks/G8oWpZxL1ZtRVlC5GmoKHcAmDS7vyzLRXNDDdsK3flShmq UJPA== MIME-Version: 1.0 X-Received: by 10.152.37.229 with SMTP id b5mr7793559lak.40.1404469535788; Fri, 04 Jul 2014 03:25:35 -0700 (PDT) Sender: rizzo.unipi@gmail.com Received: by 10.114.177.234 with HTTP; Fri, 4 Jul 2014 03:25:35 -0700 (PDT) In-Reply-To: <20140704101626.GB58753@zxy.spb.ru> References: <20140701091252.GB3443@brick> <20140701231305.GA37246@zxy.spb.ru> <20140702112609.GA85758@zxy.spb.ru> <20140702203603.GO5102@zxy.spb.ru> <20140703091321.GP5102@zxy.spb.ru> <20140704101626.GB58753@zxy.spb.ru> Date: Fri, 4 Jul 2014 12:25:35 +0200 X-Google-Sender-Auth: e1Z0RDb7BUXsZx_QzJznnRFjdds Message-ID: Subject: Re: FreeBSD iscsi target From: Luigi Rizzo To: Slawa Olhovchenkov Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18 Cc: Kevin Oberman , Sreenivasa Honnur , FreeBSD Current , Nikolay Denev X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Jul 2014 10:25:39 -0000 On Fri, Jul 4, 2014 at 12:16 PM, Slawa Olhovchenkov wrote: > On Thu, Jul 03, 2014 at 08:39:42PM -0700, Kevin Oberman wrote: > > > > > > > In real world "Reality is quite different than it actually is". > > > > > > > http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-6500-s= eries-switches/white_paper_c11-696669.html > > > > > > See "Packet Path Theory of Operation. Ingress Mode". > > > > > > > > Yep. It is really crappy LAGG (fixed three-tupple hash... yuck!) and is > > really nothing but 4 10G Ethernet ports using a 40G PHY in yhe 4x10G > form. > > > > Note that they don't make any claim of 802.3ba compliance. It only stat= es > > that "40 Gigabit Ethernet is now part of the IEEE 802.3ba standard." So > it > > is, but this device almost certainly predates the completion of the > > standard to get a product for which there was great demand. It's a data > > center product and for typical cases of large numbers of small flow, it > > should do the trick. Probably does not interoperate with true 80-2.3ba > > hardware, either. > > > > My boss at the time I retired last November was on the committee that > wrote > > 802.3ba. He would be a good authority on whether the standard has any > vague > > wording that would allow this, but he retired 5 month after I did and I > > have no contact information for him. But I'm pretty sure that there is = no > > way that this is legitimate 40G Ethernet. > > 802.3ba describe only end point of ethernet. > ASIC, internal details of implemetations NICs, switches, fabrics -- > out of standart scope. > Bottleneck can be in any point of packet flow. > In first pappers of netmap test demonstarated NIC can't do saturation > of 10G in one stream 64 bytes packet -- need use multiple rings for > transmit. > =E2=80=8Bthat was actually just a configuration issue which since then has been =E2=80=8Bresolved. The 82599 can do 14.88 Mpps on a single ring (and is the only 10G nic i have encountered who can do so). Besides, performance with short packets has nothing to do with the case you were discussing, namely throughput for a single large flow. > I think need use general rule: one flow transfer can hit performance > limitation. > =E2=80=8BThis is neither a useful nor it is restricted to a single flow. Everything "can" underperform depending on the hw/sw configuration, but not necessarily has to. cheers luigi