From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH net-next 3/4] tcp: add SACK compression
Date: Thu, 17 May 2018 10:15:16 -0700
Message-ID: <CANn89i+kSB9WCNVFyJsdS3wvf=wVHPCFx=D3ZopNAxs4vEcSEg@mail.gmail.com>
References: <20180517121213.43559-1-edumazet@google.com> <20180517121213.43559-4-edumazet@google.com>
 <CADVnQykgM_8WoZrtYYMOm7s7=Ozqdxz56fgvB-AFwX4G1gBL=A@mail.gmail.com>
 <58bcf9c0-e4f0-691d-8d6a-40ff3629f500@gmail.com> <CADVnQymTZ-dfU65kJYAVrb4eEWkou_+bd8ZOCxE9sPUn=ZCtxg@mail.gmail.com>
 <CAK6E8=e=L3oDLwAJze0Af_YXYBOBvpWTZHpBSPcGjUmuvLCKXQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Cc: Neal Cardwell <ncardwell@google.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= <toke@toke.dk>,
        Soheil Hassas Yeganeh <soheil@google.com>,
        Christoph Paasch <cpaasch@apple.com>
To: Yuchung Cheng <ycheng@google.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mail-wm0-f67.google.com ([74.125.82.67]:52757 "EHLO
        mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751409AbeEQRPa (ORCPT
        <rfc822;netdev@vger.kernel.org>); Thu, 17 May 2018 13:15:30 -0400
Received: by mail-wm0-f67.google.com with SMTP id w194-v6so9714375wmf.2
        for <netdev@vger.kernel.org>; Thu, 17 May 2018 10:15:29 -0700 (PDT)
In-Reply-To: <CAK6E8=e=L3oDLwAJze0Af_YXYBOBvpWTZHpBSPcGjUmuvLCKXQ@mail.gmail.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Thu, May 17, 2018 at 9:59 AM Yuchung Cheng <ycheng@google.com> wrote:
> >
> > Thanks for implementing this! Overall this patch seems nice to me.
> >
> > Acked-by: Neal Cardwell <ncardwell@google.com>
> >
> > BTW, I guess we should spread the word to maintainers of other major TCP
> > stacks that they need to be prepared for what may be a much higher
degree
> > of compression/aggregation in the SACK stream. Linux stacks going back
many
> > years should be fine with this, but I'm not sure about the other major
OSes
> > (they may only allow sending one MSS per ACK-with-SACKs received).
> Patch looks really good but Neal's comment just reminds me a potential
> legacy issue.

> I recall at least Apple and Windows TCP stacks still need 3+ DUPACKs
> (!= a SACK covering 3+ packets) to trigger fast recovery. Will we have
> an issue there interacting w/ these stacks?


Then we should revert GRO :)

Really it is time for these stacks to catch up, or give up to QUIC :/