From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-x22d.google.com (mail-la0-x22d.google.com [IPv6:2a00:1450:4010:c03::22d]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 0067521F3D6 for ; Thu, 14 May 2015 08:32:48 -0700 (PDT) Received: by labbd9 with SMTP id bd9so73300127lab.2 for ; Thu, 14 May 2015 08:32:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=OrFa9vMnkJ4rxQStbmdoO3zRzs0Vo8husgDJZcSx01k=; b=CHcbbcs3IG2WIcHiDNZxT6BDL83lMZRhpLWmGhIco6hvC+hMCUaVcMyTA+J3RVOV1z UoggmbZYBvcC+7yuXHtHMDm5MuLwtvmeYW5l2qOtk4nIriLszk+rWol5EjuFLYpv/uZO kZv77MyjjcJ9f31s212IJd9b/wxWP9SX5oxrUoGn5W6CE/RtK1YvXaRcLNIY5layIe3k Q172C6Ne3WQ77jLRFKMhEqFJzwOwMP5WgAA7uiSao//o1xLbabJroJQjE6Smh6A1GwrU U8pETU5Xsj798L/mX9wBKoYYw4U45mzIFguFwFg0H+MZwogVxiBuPupHHz9/vCbxF8dK Sszg== X-Received: by 10.112.126.136 with SMTP id my8mr3656104lbb.18.1431617566101; Thu, 14 May 2015 08:32:46 -0700 (PDT) Received: from [192.168.43.25] (37-33-102-97.bb.dnainternet.fi. [37.33.102.97]) by mx.google.com with ESMTPSA id c5sm6225744lac.15.2015.05.14.08.32.41 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 14 May 2015 08:32:45 -0700 (PDT) Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) From: Jonathan Morton In-Reply-To: <664C6B9D-67C2-4614-A9B0-140D3BEEA4AD@gmx.de> Date: Thu, 14 May 2015 18:32:33 +0300 Content-Transfer-Encoding: quoted-printable Message-Id: <444770E9-51C0-4935-8E00-5008CDB388E5@gmail.com> References: <554F64E1.6000609@gmail.com> <554F9594.60808@gmail.com> <50DB1E31-61AE-4298-B80F-8C6F7487C99B@gmail.com> <002A5BFC-5511-4995-8785-370251F24083@gmx.de> <38FFDA3C-2F67-4831-B316-DF8CC7EF0167@gmail.com> <664C6B9D-67C2-4614-A9B0-140D3BEEA4AD@gmx.de> To: Sebastian Moeller X-Mailer: Apple Mail (2.2098) Cc: cake@lists.bufferbloat.net Subject: Re: [Cake] openwrt build with latest cake and other qdiscs X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 May 2015 15:33:21 -0000 > On 14 May, 2015, at 17:57, Sebastian Moeller wrote: >=20 > I am probably daft, but looking at the comment in front of = skb_gso_network_seglen() (see = http://lxr.free-electrons.com/ident?i=3Dskb_gso_network_seglen ) makes = me thick there is a way of getting the lengths of the individual = segments of a GSO aggregate All the segments (except possibly the last) will be MTU sized, I = suspect. The necessary headers would be duplicated, with fresh = (sequential) IP IDs, adjusted TCP sequence numbers and recalculated = checksums. The size of the last segment (and maybe the number of = segments) would depend on the header size, since a bigger header (due = eg. to TCP timestamps) reduces the payload per packet. I don=92t immediately see how to reliably calculate the sizes of the = resulting packets. So I=92d rather split them up and be certain about = it, in the cases where it matters most, and take the size of the = aggregate as sufficiently reliable in other cases. - Jonathan Morton