From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ondar.cablelabs.com (ondar.cablelabs.com [192.160.73.61]) by huchra.bufferbloat.net (Postfix) with ESMTP id 7ED1D21F1AC for ; Tue, 21 Jan 2014 15:56:03 -0800 (PST) Received: from kyzyl.cablelabs.com (kyzyl [10.253.0.7]) by ondar.cablelabs.com (8.14.7/8.14.7) with ESMTP id s0LNtwIG015828; Tue, 21 Jan 2014 16:55:58 -0700 Received: from exchange.cablelabs.com (10.5.0.19) by kyzyl.cablelabs.com (F-Secure/fsigk_smtp/407/kyzyl.cablelabs.com); Tue, 21 Jan 2014 16:55:57 -0700 (MST) X-Virus-Status: clean(F-Secure/fsigk_smtp/407/kyzyl.cablelabs.com) Received: from EXCHANGE.cablelabs.com ([fe80::797a:96d1:3c53:18ee]) by EXCHANGE.cablelabs.com ([fe80::797a:96d1:3c53:18ee%11]) with mapi id 14.03.0174.001; Tue, 21 Jan 2014 16:55:57 -0700 From: Greg White To: Dave Taht , bloat Thread-Topic: [Bloat] pie aqm finally landed in Linux Thread-Index: AQHPFfgZ6uxvrNIrSkKofqXUC6+2CpqP3LSA Date: Tue, 21 Jan 2014 23:55:56 +0000 Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/14.3.9.131030 x-originating-ip: [10.4.10.154] Content-Type: text/plain; charset="iso-8859-1" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [Bloat] pie aqm finally landed in Linux X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Jan 2014 23:56:10 -0000 Dave, We're allowing target to be configurable, but providing a default value of 10ms. In the DOCSIS CM implementation of PIE we don't track historic data rates via an estimation window, instead we utilize the state of the token bucket rate shaper to predict the rate transitions from the known peak rate (power boost) to the known sustained rate. This is both a) much simpler and b) much more accurate. The 3.1 spec and the 3.0 ECO do include AQM requirements for the CMTS side as well. I agree though that reductions in buffer sizes would seem to be a quick fix in advance of AQM implementations. FYI, we've made some additional enhancements to the PIE algorithm for DOCSIS since publication of the D3.1 spec. An update is forthcoming. -Greg On 1/20/14, 8:46 AM, "Dave Taht" wrote: >http://www.spinics.net/lists/netdev/msg264935.html > >Hat off to vijay and the pie folk at cisco who shepherded the code >through 5 releases to get it upstream! > >PIE is now mandated in DOCSIS3.1 cablemodems and the ECO for DOCSIS >3.0 went out a while ago. > >I think the mandate differs from the Linux implementation. I don't >know the size of the recomended cablelabs target nor the size of the >estimation window (?)). > >So that will improve going-upstream buffering problems dramatically. > >The linux implementation supports ECN, the DOCSIS standard does not. >The ECN work in pie has some minor problems that fq_codel doesn't >have, we hope to discuss at ietf... > >I will fold the v5 implementation of pie into cerowrt in the next release >and >see what happens. > >NOW: > >The biggest problem remaining in cable is fixing excessive downstream >buffering. Surely something can be done to remove the 1.6 seconds of >buffering I observed yesterday (at some level without needing to AQM? >Some workaround that operators can use?). Some benchmarks I ran last >night (not against pie): > >http://snapon.lab.bufferbloat.net/~d/bev/comcast_native_ipv6/ > >I sure hope the gpon, lte, and wifi folk are paying attention. > >--=20 >Dave T=E4ht > >Fixing bufferbloat with cerowrt: >http://www.teklibre.com/cerowrt/subscribe.html >_______________________________________________ >Bloat mailing list >Bloat@lists.bufferbloat.net >https://lists.bufferbloat.net/listinfo/bloat