From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x241.google.com (mail-pf0-x241.google.com [IPv6:2607:f8b0:400e:c00::241]) (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 431C43B2A2 for ; Fri, 2 Dec 2016 18:32:28 -0500 (EST) Received: by mail-pf0-x241.google.com with SMTP id c4so14185634pfb.3 for ; Fri, 02 Dec 2016 15:32:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:subject:from:to:cc:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=6PdI3E9zpyhugi7nmQXDwciegDKofKFicESl7yyogU0=; b=rg5AROICO3f7rM9cizARv9MN0xp/KQS6A+WdCKZkTjH5ieaaeDnqzMsAOUSy8kP/CL 2l+f6l6C0VsdIxeCsgWnJuPau9JgzBxxO7gMFehA4St4elDppCvsKzZaXh954m1UZ0LB GYP+tM2kuIr9f+KIFfY45+xagu5iU0AsBe7mJB0m2+tRmUHrBogLoTjQ7HWsiom8Q4m/ INV8lYVSBUwJJgqG3iu9IOrjN2rpZlGFatoMmrg4/1K3LQXS2UxxgVeUN4wbrjeKcNqI pUMjmZ+CPRG9lGrx0GdDrv9/N7BThw8z6iSJCzJgfl0GFxjRVSllD1tEWqNRMgOZoOT+ QUUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=6PdI3E9zpyhugi7nmQXDwciegDKofKFicESl7yyogU0=; b=hEMSwgZzNVH1FCSr/SJqjlMl4yx8YPf/nVl8FikkEQgkCBxkY24oNbPG4byXn2kYR6 WEwyD89ci3cJDCDINvDvnvLgUrcr3FfyaiLvQecl8xG37KgY2TDZjrJnTVgYOiarFtu4 p10HKIwiF1/qBshfW7KpAKInjxMMfa7KMrwzCcikZ6EGcM5OkqMjoZVSDGUC4St2bZmf BL63iYdAG4mi3A3CxP30+PAzT048Udze/GlzGB9IDQa4aTLIAfVjF+q1HLO1JXg2SBU3 dLrbCdcfb7KQUpjpcB40PS9XMPkChHo8WZcUfJ9cwWRtA2u6Wt6Jcvrjj5fii39dcfBi ZRCw== X-Gm-Message-State: AKaTC03MPdNmbjZS8z1YoMWyi5ZY+vdjvn4wr33k3EYDzsHLW0VK4v6EvF2LjBRCgxA1yg== X-Received: by 10.84.218.136 with SMTP id r8mr101667566pli.23.1480721547450; Fri, 02 Dec 2016 15:32:27 -0800 (PST) Received: from [172.19.22.200] ([172.19.22.200]) by smtp.googlemail.com with ESMTPSA id q27sm10120839pfd.49.2016.12.02.15.32.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 02 Dec 2016 15:32:27 -0800 (PST) Message-ID: <1480721486.18162.392.camel@edumazet-glaptop3.roam.corp.google.com> From: Eric Dumazet To: "Steinar H. Gunderson" Cc: Neal Cardwell , Jonathan Morton , "aqm@ietf.org" , bloat Date: Fri, 02 Dec 2016 15:31:26 -0800 In-Reply-To: <20161202224006.GA5065@sesse.net> References: <56F6A3AB-3A47-4178-BEFF-04E3DC23B039@gmail.com> <20161202224006.GA5065@sesse.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit 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: Fri, 02 Dec 2016 23:32:28 -0000 On Fri, 2016-12-02 at 23:40 +0100, Steinar H. Gunderson wrote: > On Fri, Dec 02, 2016 at 05:22:23PM -0500, Neal Cardwell wrote: > > Of course, if we find important use cases that don't work with BBR, we will > > see what we can do to make BBR work well with them. > > I have one thing that I _wonder_ if could be BBR's fault: I run backup over > SSH. (That would be tar + gzip + ssh.) The first full backup after I rolled > out BBR on the server (the one sending the data) suddenly was very slow > (~50 Mbit/sec); there was plenty of free I/O, and neither tar nor gzip > (well, pigz) used a full core. My only remaining explanation would be that > somehow, BBR didn't deal well with the irregular stream of data coming from > tar. (A wget between the same machines at the same time gave 6-700 Mbit/sec.) > > I will not really blame BBR here, since I didn't take a tcpdump or have time > to otherwise debug properly (short of eliminating the other things I already > mentioned); most likely, it's something else. But if you've ever heard of > others with similar issues, consider this a second report. :-) > > /* Steinar */ It would be interesting to get the chrono stats for the TCP flow, with an updated ss/iproute2 command and the kernel patches : efd90174167530c67a54273fd5d8369c87f9bd32 tcp: export sender limits chronographs to TCP_INFO b0f71bd3e190df827d25d7f19bf09037567f14b7 tcp: instrument how long TCP is limited by insufficient send buffer 5615f88614a47d2b802e1d14d31b623696109276 tcp: instrument how long TCP is limited by receive window 0f87230d1a6c253681550c6064715d06a32be73d tcp: instrument how long TCP is busy sending 05b055e89121394058c75dc354e9a46e1e765579 tcp: instrument tcp sender limits chronographs