From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [PATCH iproute2-next] Add tc-BPF example for a TCP pure ack recognizer Date: Wed, 2 May 2018 09:22:24 -0600 Message-ID: References: <1525199561-9302-1-git-send-email-dave.taht@gmail.com> <96fb372d-4fc8-77db-e971-6b9540d8ad26@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Linux Kernel Network Developers To: Dave Taht Return-path: Received: from mail-pf0-f181.google.com ([209.85.192.181]:40541 "EHLO mail-pf0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752397AbeEBPW1 (ORCPT ); Wed, 2 May 2018 11:22:27 -0400 Received: by mail-pf0-f181.google.com with SMTP id f189so12073516pfa.7 for ; Wed, 02 May 2018 08:22:27 -0700 (PDT) In-Reply-To: Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 5/1/18 10:51 PM, Dave Taht wrote: > On Tue, May 1, 2018 at 9:12 PM, David Ahern wrote: >> On 5/1/18 12:32 PM, Dave Taht wrote: >>> ack_recognize can shift pure tcp acks into another flowid. >>> --- >>> examples/bpf/ack_recognize.c | 98 ++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 98 insertions(+) >>> create mode 100644 examples/bpf/ack_recognize.c >>> >>> diff --git a/examples/bpf/ack_recognize.c b/examples/bpf/ack_recognize.c >>> new file mode 100644 >>> index 0000000..5da620c >>> --- /dev/null >>> +++ b/examples/bpf/ack_recognize.c >>> @@ -0,0 +1,98 @@ >>> +/* SPDX-License-Identifier: GPL-2.0 */ >>> +/* >>> + * Copyright 2017 Google Inc. >> >> 2017?? it's 2018. Did you write this last year and just now posting? > > November, 2017? Shortly prior to you taking iproute2-next off of steven's hands. ok, just checking > > It was the first stage of a proof of concept showing (eventually) that > a simple ack decimator/filter (like "drop every other ack", or simple > "drop head" in the supplied example) had a ton of problems, and that > to filter out acks correctly to any extent, it needed to peer back > into the queue. (see the sch_cake ack-filter controversy on-going on > this list) > > While it's better than what is in wondershaper, I wouldn't recommend > anyone use it. It was, however, useful in acquiring a gut feel for > what several other broken ack filters might be doing in the field. I > submitted it as a possibly useful example for showing off tc-bpf and > to add fuel to the ack-filter fire under cake. > > I can clean it up, SPF it, etc, if you want it. Otherwise, sorry for the noise. I'm fine with the example, just prefer magic numbers to be clarified.