From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x244.google.com (mail-lf0-x244.google.com [IPv6:2a00:1450:4010:c07::244]) (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 9A6063B2A3 for ; Sat, 3 Dec 2016 16:38:21 -0500 (EST) Received: by mail-lf0-x244.google.com with SMTP id o20so25180672lfg.3 for ; Sat, 03 Dec 2016 13:38:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=nVj/ZMbh99W2OtDOYHHzy8VP4iRHl+ZzL2qhUuJn1Ng=; b=aMQCIfsqUvoDFxM4BBNDqQJk0jGonoxWjwTZTTy/O+/d6BPgu4Dfl3IQGQovkUTLB9 Iu3J3ZRtILisbeJNL9Lh9aEhWYA58GloqOcFufnMwHKZVIRyxGj+d4FM1TjFcv83T6Bn LmUITjn9RPFmfOKa9bxfunt0jfpSE/Co8boRfYJijhPl2AzLv7nLfwm8YCfOAfPpXCRk g+x1aBvuSIOpWxKJhsrSBe7htuvAaYbtaEaPCXrLt99vffmYaC53pVfYc6Qe11qq8bUh 0qDCW4TJu2th87Dr7H6z3L+J+731OXzPiOjB8VvgACg9lj9WyvVS50ePCdcUyRWt0d9J DW7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=nVj/ZMbh99W2OtDOYHHzy8VP4iRHl+ZzL2qhUuJn1Ng=; b=lNZErYhCp3hDfAj5busmirc4+laGn7Rd0qkRoKRaTzXRwCJ3JaARaKXHgkvKkmL6Nu vcKvud9uiAfppwQGDTzPIPrngFPp/F9CC+ZGGpFB7vbInhpb6zfJJ1vyoHIOjjze2p9o IUzyFJaGVmt2PMriDyO02YSHCWQ3ZWULxWWccay9vZ3+f1R/UTCuw6MsnxyRWAIdorWy GTOG1MaUbqf0uxwP+f38lDNrvdWpavQ+N2Ww2r5k5IAhwfyTbwDcPWrBhipu4ZaOUP3A HLUBbMxBS0VIyRD4Yk0GIeqLqtalfB6A/Ku1ULfBwpjUL/pSY1MN8w4UoiXgLTRUhL0K UxvA== X-Gm-Message-State: AKaTC034rxKFu35tdHpgfyMpEBc5eBBQyPiYIVmUFMOEfqxGk41YQ2Pqbr/XHa5i5xtdsA== X-Received: by 10.25.228.88 with SMTP id b85mr20279238lfh.100.1480801100325; Sat, 03 Dec 2016 13:38:20 -0800 (PST) Received: from [192.168.100.13] (37-33-82-144.bb.dnainternet.fi. [37.33.82.144]) by smtp.gmail.com with ESMTPSA id 67sm1749444ljf.35.2016.12.03.13.38.19 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 03 Dec 2016 13:38:19 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Jonathan Morton In-Reply-To: <1480799260.18162.418.camel@edumazet-glaptop3.roam.corp.google.com> Date: Sat, 3 Dec 2016 23:38:18 +0200 Cc: "Steinar H. Gunderson" , Neal Cardwell , "aqm@ietf.org" , bloat Content-Transfer-Encoding: quoted-printable Message-Id: <567310A9-77A4-4AA6-8AED-08EC819DFD8F@gmail.com> References: <56F6A3AB-3A47-4178-BEFF-04E3DC23B039@gmail.com> <20161202224006.GA5065@sesse.net> <1480721486.18162.392.camel@edumazet-glaptop3.roam.corp.google.com> <20161203191353.GA972@sesse.net> <1480796415.18162.408.camel@edumazet-glaptop3.roam.corp.google.com> <9A821B94-143B-446F-8852-2EB0158DD57C@gmail.com> <1480799260.18162.418.camel@edumazet-glaptop3.roam.corp.google.com> To: Eric Dumazet X-Mailer: Apple Mail (2.3124) Subject: Re: [Bloat] TCP BBR paper is now generally available 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: Sat, 03 Dec 2016 21:38:21 -0000 > On 3 Dec, 2016, at 23:07, Eric Dumazet wrote: >=20 > I do not attend IETF meetings so maybe my words are not exact. >=20 > What I meant was that we receive ACKS in bursts, with huge gaps = between > them. >=20 > Look at tsval/tsecr, and that all ACKS are received in a 20 usec time > window, covering data that was sent in a 5 ms window. Nevertheless, there are no acks obviously *missing*. Decimation would = be aggregation of acks such that all but the last (over some interval) = is dropped. Here, they are merely delivered in rapid succession. It could be that the receiver has poor receive-interrupt latency, or = that it is aggregating the reverse send path too heavily. The variable = spacing within the ack burst (in particular, in both examples the gap = between first and second is larger than the rest) favours the former = explanation. - Jonathan Morton=