From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sonic316-16.consmr.mail.bf2.yahoo.com (sonic316-16.consmr.mail.bf2.yahoo.com [74.6.130.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 69B733CB38 for ; Wed, 4 Apr 2018 09:39:11 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rogers.com; s=s2048; t=1522849151; bh=eH9pPB4NYlARWavjyVEv97p+N2J/SGC/MiESbq/LMDQ=; h=Reply-To:Subject:To:References:From:Date:In-Reply-To:From:Subject; b=F9zwL3hDcwr1Nvd02Q7HtIVbrYRGfQBO0DLSkvHUCbN0Kf3sy41N9UTR+VCscGp1p5i02r23eskfGLnKZw+9LBYXytxwA2r0Xu6sCUPIj4wxtXSmendBAgK8Vj1TvOmhAaRV5L5IKHZzNNLg6mLaK0nkadMBdLybFTwRfowksfZlrMqrq0tcVvX/Bri6WRJmiCXe6Eb5UMOuNauPc/C3xgsHS47xiua4bidBcm0gStCUtRPSVHFUbjWTXGzun7KbTGDj0v36/UvIErsC+vsrWmxpJTZkcw1iCKzBgyr1TyHNw98V2lcLtfbFNaWig2A3IAPz3uda1csV07IJZ51Gow== X-YMail-OSG: xxoLqRsVM1nTuXExDodBD3bjakBwA38cW_1eJqUZAtDGNhPIc.oUu2EgrawWCu1 RCXkEgAgPqOLJ4vZPrjCej6.EwAUrG6Ad32tW2_FJkLXwRn.OdCNb3z7YWty25METsM13mtT0Fkd EzgP833JUk_UK0SPwSWra_voGujxSQoTrd0U07XlzjDskygi.h3dFWlZu0ht6BGtUkrK0fgm25E2 HYKyZLj.tZ6qnF7F_cQ3evP7uxdFYIcbct1T360v6gUVHUQUJ2WUMJdPJSUzVX84N3FCUngsqksl ls8gFq22nvcImVa.IBIUolxu1slg4ZBUlGb9IAnlP1E8csMbc_Wdkm70k182iCmbVzAdaGyWVOk3 6o7_QfE8F0a3fM5knRKX1lgVG3Guy0p_YaJQigmoQM_IzzjP.YZcULqwgyIjjcoEK_DTCstoR5wu CHCicJddwKAoKXs9el5cyUAM6GxwjYtZLXtH_eXXhnk.N83F3NP6K90LVh5ymb_rn44_SFo5_qFN k9KaZfZspu9.nyOpiM363YdFy8mNzPw6CErQbEsrXoZjDgYOwlVKI2XIybPA- Received: from sonic.gate.mail.ne1.yahoo.com by sonic316.consmr.mail.bf2.yahoo.com with HTTP; Wed, 4 Apr 2018 13:39:11 +0000 Received: from asrd.casalemedia.com (EHLO [10.4.10.183]) ([192.139.80.1]) by smtp428.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 2f3a897f1c334794612d4c3b916cfad2; Wed, 04 Apr 2018 13:39:07 +0000 (UTC) Reply-To: davecb@spamcop.net To: bloat@lists.bufferbloat.net References: <50e57074-4ca5-59f7-f010-d9b2b845a8a7@rogers.com> <8DE589C3-9537-416D-AC7C-9250464869F9@gmail.com> From: David Collier-Brown Message-ID: Date: Wed, 4 Apr 2018 09:39:07 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------074A96DAD2AB53EA9A8379D8" Content-Language: en-US Subject: Re: [Bloat] Seen in passing: mention of Valve's networking scheme and RFC 5348 X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Apr 2018 13:39:11 -0000 This is a multi-part message in MIME format. --------------074A96DAD2AB53EA9A8379D8 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit The phenomenon is called "lava flow", and is a classic anti-pattern illustrated at http://antipatterns.com/lavaflow.htm Their approach to fixing is ancient, though: there are correctness-preserving refactorings for some of the problem space. Alas, I don't know if middleboxes are correctable... maybe if they are ones which only care about the IP layer? --dave On 04/04/18 08:45 AM, Jesper Louis Andersen wrote: > On Tue, Apr 3, 2018 at 5:04 PM Jim Gettys > wrote: > > ​To get to really good RTT's (with low jitter), you still need > ​fq_codel (or similar).  You just can't get there by hacking TCP > no matter how hard you try... > > > I agree with you on all points here. However, any change which patches > an existing bad system is far more likely to win in the long run, also > if it is bad in some way. Momentum is a killer of good solutions. I > wish I had a ramification for this observation, but I currently don't. > > My hunch is that every new generation of young programmers wants to > put their mark on the system. As a result, they take what worked well > on level N-1 and proceed to build N on top of it. But the beanstalk > never withers, so each level is present in said stack, still, after > all these years. > > (Aside: The codel approach also has worked really well for me > internally in Erlang systems as a way to maintain queue load. Far > better than many other flow control schemes). > > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb@spamcop.net | -- Mark Twain --------------074A96DAD2AB53EA9A8379D8 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
The phenomenon is called "lava flow", and is a classic anti-pattern illustrated at http://antipatterns.com/lavaflow.htm
Their approach to fixing is ancient, though: there are correctness-preserving refactorings for some of the problem space.

Alas, I don't know if middleboxes are correctable... maybe if they are ones which only care about the IP layer?

--dave

On 04/04/18 08:45 AM, Jesper Louis Andersen wrote:
On Tue, Apr 3, 2018 at 5:04 PM Jim Gettys <jg@freedesktop.org> wrote:
​To get to really good RTT's (with low jitter), you still need ​fq_codel (or similar).  You just can't get there by hacking TCP no matter how hard you try...


I agree with you on all points here. However, any change which patches an existing bad system is far more likely to win in the long run, also if it is bad in some way. Momentum is a killer of good solutions. I wish I had a ramification for this observation, but I currently don't.

My hunch is that every new generation of young programmers wants to put their mark on the system. As a result, they take what worked well on level N-1 and proceed to build N on top of it. But the beanstalk never withers, so each level is present in said stack, still, after all these years.

(Aside: The codel approach also has worked really well for me internally in Erlang systems as a way to maintain queue load. Far better than many other flow control schemes).


_______________________________________________
Bloat mailing list
Bloat@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/bloat



-- 
David Collier-Brown,         | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
davecb@spamcop.net           |                      -- Mark Twain
--------------074A96DAD2AB53EA9A8379D8--