From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail1.sandvine.com (Mail1.sandvine.com [64.7.137.134]) by huchra.bufferbloat.net (Postfix) with ESMTP id 65F7521F98C for ; Tue, 11 Aug 2015 10:14:49 -0700 (PDT) Received: from BLR-EXCHP-2.sandvine.com (192.168.196.172) by WTL-EXCHP-2.sandvine.com (192.168.194.177) with Microsoft SMTP Server (TLS) id 14.3.195.1; Tue, 11 Aug 2015 13:14:47 -0400 Received: from WTL-EXCHP-1.sandvine.com ([fe80::ac6b:cc1e:f2ff:93aa]) by blr-exchp-2.sandvine.com ([fe80::6c6d:7108:c63c:9055%14]) with mapi id 14.03.0181.006; Tue, 11 Aug 2015 13:14:46 -0400 From: Jeff Weeks To: "codel@lists.bufferbloat.net" Thread-Topic: drop state short-circuit... Thread-Index: AdDUWTi+z9YPmBhVTMqSiLkA0ZrNhQ== Date: Tue, 11 Aug 2015 17:14:46 +0000 Message-ID: <274D3A0FA900FD47AA6B56991AAA32FDC53BB45E@wtl-exchp-1.sandvine.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [192.168.214.43] Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: [Codel] drop state short-circuit... X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Aug 2015 17:15:17 -0000 Hello, I originally posted this in the aqm list; re-posted to this, more appropria= te, list: There exists a short-circuit into a "deeper" drop state if we were previous= ly and recently in a drop state. I understand the need for this, but I'm c= urious where the '16' came from? How was this decided upon? For example, here's the ns3 implementation: /* * if min went above target close to when we last went below it * assume that the drop rate that controlled the queue on the * last cycle is a good starting point to control it now. */ int delta =3D m_count - m_lastCount; if (delta > 1 && CoDelTimeBefore (now - m_dropNext, 16 * Time2CoD= el (m_interval))) { m_count =3D delta; NewtonStep (); } If I read this correctly, it says; If we have previously dropped for more than one interval, and have re-enter= ed the drop state in less then 16 intervals from the previous drop state, t= hen short circuit count to the delta... but why 16 intervals? --Jeff