From owner-freebsd-net@FreeBSD.ORG Wed Feb 26 21:28:21 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BE4F1451 for ; Wed, 26 Feb 2014 21:28:21 +0000 (UTC) Received: from mail-vc0-x236.google.com (mail-vc0-x236.google.com [IPv6:2607:f8b0:400c:c03::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 791141DAE for ; Wed, 26 Feb 2014 21:28:21 +0000 (UTC) Received: by mail-vc0-f182.google.com with SMTP id id10so1579064vcb.13 for ; Wed, 26 Feb 2014 13:28:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=pTd68SAq+azO3ZQZiW2x2sZApI+lMnSF9S6dctMpy0Y=; b=qLR9MylIFGt4TKR7dywVlDGTaAukghtUGdVgbPp7TW2D1vOjmgga8y7VqoddscWQJD HezRF0LiA9PQIQbrfYGgY6tQRefQ2ucW+5Pamqt+EGUxnF4XS/FN9dCKqIp8ENEGqEjl 7mRR/+xCOYrNVIgFWeX+VQOU7ePhWWRdvXmrUD4QofpgNoepxXr0MNi0xb5+bQGM9Dem jt1q8nuZPdswvYKvpn+5a62jJ4b5/QVriGoNJJL1o6wmiY7lHrbihE3FdyoMKtk8hvcu PCdvIYBiNs0lFoGd7x59xIJK6aFZE+pU1lfsbnpGh3dVfL6fQcU/eRGn1slTZRDvc4sp hSbQ== MIME-Version: 1.0 X-Received: by 10.220.109.1 with SMTP id h1mr7591850vcp.20.1393450100568; Wed, 26 Feb 2014 13:28:20 -0800 (PST) Received: by 10.221.11.135 with HTTP; Wed, 26 Feb 2014 13:28:20 -0800 (PST) In-Reply-To: References: <20140226180736.GV92037@funkthat.com> Date: Wed, 26 Feb 2014 13:28:20 -0800 Message-ID: Subject: Re: TSO From: Jack Vogel To: Scott Long Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: FreeBSD Net , Sami Halabi X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Feb 2014 21:28:21 -0000 Nah that wouldn't be very practical would it :) I was thinking the max segment value could be kept in the interface struct, but as I think about it I guess that wouldn't really help. So, you have other ideas Scott?? Jack On Wed, Feb 26, 2014 at 1:13 PM, Scott Long wrote: > Are you proposing that the network stack track the physical memory segment > details of the mbufs as they are formed and chained together? > > Scott > > On Feb 26, 2014, at 10:27 AM, Jack Vogel wrote: > > > Drivers have to work with whatever the requirements/limitations of the > > hardware, > > if you have a 5 lb sack you shouldn't be surprised if some drops when you > > shove > > 6 lbs at it :) > > > > Why not have this limit in the interface so the stack can avoid exceeding > > it? > > > > Jack > > > > > > > > > > On Wed, Feb 26, 2014 at 10:07 AM, John-Mark Gurney > wrote: > > > >> Sami Halabi wrote this message on Wed, Feb 26, 2014 at 19:37 +0200: > >>> I'm reading (almost) all mailing emails in mailig list... > >>> > >>> Almost every / many problem in network performancr / packets loss ended > >> up > >>> suggesting disabling TSO. > >>> > >>> I wonder why.. Is it a bug in the implementation? Or bybdesign? > >>> What are the usecases that TSO is needed? Myabe it should be disabled > bt > >>> default? > >> > >> It looks like most of the problems are in drivers that don't handle > >> packets with a large number of segments properly... The problem is > >> that some drivers limit to how segments a packet can be broken into, and > >> then if they receive such a packet, instead of doing their darnest to > >> deliver it, they drop it... > >> > >> There are some patches that help address the issue... > >> > >> Drivers should complain more loudly when a packet gets dropped by the > >> driver, since it is likely that the OS may retry the same packet, > >> just to have it fail, though sometimes it'll try a different set, and > >> it might go through, so all the user may notice is a slight lag if > >> they notice anything at all... > >> > >> -- > >> John-Mark Gurney Voice: +1 415 225 5579 > >> > >> "All that I will do, has been done, All that I have, has not." > >> _______________________________________________ > >> freebsd-net@freebsd.org mailing list > >> http://lists.freebsd.org/mailman/listinfo/freebsd-net > >> To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > >> > > _______________________________________________ > > freebsd-net@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-net > > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > >