IETF Logo Mail Archive

Re: [aqm] Questioning each PIE heuristic

Jonathan Morton <chromatix99@gmail.com> Thu, 30 March 2017 09:08 UTC

Return-Path: <chromatix99@gmail.com>
X-Original-To: aqm@ietfa.amsl.com
Delivered-To: aqm@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E9D6D128B4E; Thu, 30 Mar 2017 02:08:36 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.45
X-Spam-Level:
X-Spam-Status: No, score=-2.45 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id gA5qd5fQIvyR; Thu, 30 Mar 2017 02:08:35 -0700 (PDT)
Received: from mail-lf0-x241.google.com (mail-lf0-x241.google.com [IPv6:2a00:1450:4010:c07::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 349C51241FC; Thu, 30 Mar 2017 02:08:35 -0700 (PDT)
Received: by mail-lf0-x241.google.com with SMTP id n78so3968467lfi.3; Thu, 30 Mar 2017 02:08:35 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=jDkU2XksMyT27XP4ClXrfKmLPIDeMyE1aa9rZCXiBgk=; b=erFIRMenn3q044tt3Gxk3zGZOqiQCjPcyh/VBchL//oRO5HBMMjF3ZDDaNt4LJkO1/ JIoHcgnNvJxFdRY4h/Z8zXhKyH22vWB1X0vXPE6Sy/ZaHndUGeho31H5DrIzGP1mAgCo 7Z+7zgjVIlWoPDv709Iz8pCvBLctnpV6R4jCtePPYEE0ES1HlWSK03YvxnnUURb/3FSS auWbM2YL9mYrrLUUPyL1ryvU6YmPbFkJMYST/WyRcejwEvWEhzqCC8ny1KPp6v/MiQgV 2WDChiolkGmytg4B5uBPfiuQvqUyXZ7nadu5imGD3wnard08g8QfFez92XI9I2u2gC27 qkbg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=jDkU2XksMyT27XP4ClXrfKmLPIDeMyE1aa9rZCXiBgk=; b=BjLQQquSuR1UivCHwQrnNjalJyKQy5Qe+8xEx10p+S4Sh74JDEctdDJf478bZSDom6 WNoclJnvu/dNJfLGFgdBgJmhWmXUWKE9EqafWU/0NrKOXNZ34Z0ZwQyifpqCvM+cwtJq PT+/3Sv80ELiKk9OPIqJpoT6KVYEHsgfjeOBTCqldTe/2SjMHDCtq9QxQVUyzPeRuF/S LwxcMBE7Zr3mOLSTyLYyRnraUf4PWvzlHIHzqIsG78fa6NdgwM2bfGGS5HHu1uWkjQ8Y GbmzlbG5nQCtsPdekskKDDL07pZA/NpyTuJTD7qzapqolT4hFAmCDoBIxFPMt/TJclRe gjvg==
X-Gm-Message-State: AFeK/H2GVOo/VqsDToeX2NB/EDu+wF0L0cTMRMM2PkDvsDT2dBW5olnWI64PCKH2bzrDsA==
X-Received: by 10.25.204.9 with SMTP id c9mr1266515lfg.107.1490864913502; Thu, 30 Mar 2017 02:08:33 -0700 (PDT)
Received: from [192.168.100.14] (37-219-158-10.nat.bb.dnainternet.fi. [37.219.158.10]) by smtp.gmail.com with ESMTPSA id t30sm250424ljd.39.2017.03.30.02.08.31 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 30 Mar 2017 02:08:32 -0700 (PDT)
Content-Type: text/plain; charset="utf-8"
Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\))
From: Jonathan Morton <chromatix99@gmail.com>
In-Reply-To: <99a7b737-fc3c-efd0-b6c8-d71a089b7de8@bobbriscoe.net>
Date: Thu, 30 Mar 2017 12:08:29 +0300
Cc: "Rong Pan (ropan)" <ropan@cisco.com>, Greg White <g.white@CableLabs.com>, "FredBaker.IETF@gmail.com" <FredBaker.IETF@gmail.com>, AQM IETF list <aqm@ietf.org>, tsvwg IETF list <tsvwg@ietf.org>
Content-Transfer-Encoding: quoted-printable
Message-Id: <FB0F3D38-63E2-441E-BAB4-2541D7E9FE94@gmail.com>
References: <9ddba389-e368-9050-3b14-aa235c99fcb8@bobbriscoe.net> <D4FDD717.2636D%ropan@cisco.com> <77D4FC66-C99F-49D0-BB73-27A0CEF70F31@gmail.com> <99a7b737-fc3c-efd0-b6c8-d71a089b7de8@bobbriscoe.net>
To: Bob Briscoe <ietf@bobbriscoe.net>
X-Mailer: Apple Mail (2.3124)
Archived-At: <https://mailarchive.ietf.org/arch/msg/aqm/i6c3LjLbmKyLMFM2VCKasqZSdk4>
Subject: Re: [aqm] Questioning each PIE heuristic
X-BeenThere: aqm@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: "Discussion list for active queue management and flow isolation." <aqm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/aqm>, <mailto:aqm-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/aqm/>
List-Post: <mailto:aqm@ietf.org>
List-Help: <mailto:aqm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/aqm>, <mailto:aqm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 30 Mar 2017 09:08:37 -0000

> On 30 Mar, 2017, at 10:46, Bob Briscoe <ietf@bobbriscoe.net> wrote:
> 
> For PI2 we removed all but 2 and it worked the same or better than PIE in all our tests. I have been assessing each of the other 7 one by one for reinstatement. So far I've rejected 6. I think I can reject this last one by making the sampling time of the base PI algo dependent on the max link rate. Then when the queue goes idle, the base PI algo will decay drop down to zero no slower than the queue drains, without needing this extra heuristic.

That’s fair enough.

It sounds like the fairly coarsely discrete time intervals in PIE are the main justification for this particular heuristic, so it might be sufficient to document that WRT PIE itself.  Using finer time intervals is clearly a better choice for the future.

 - Jonathan Morton

v2.23.0 | Report a Bug | By Email