From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [IPv6:2001:67c:29f4::29]) (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 A677D3B2A2 for ; Fri, 2 Dec 2016 17:40:11 -0500 (EST) Received: from pannekake.samfundet.no ([2001:67c:29f4::50] ident=unknown) by cassarossa.samfundet.no with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1cCwUw-0007st-MJ; Fri, 02 Dec 2016 23:40:08 +0100 Received: from sesse by pannekake.samfundet.no with local (Exim 4.84_2) (envelope-from ) id 1cCwUw-00053H-Jk; Fri, 02 Dec 2016 23:40:06 +0100 Date: Fri, 2 Dec 2016 23:40:06 +0100 From: "Steinar H. Gunderson" To: Neal Cardwell Cc: Jonathan Morton , "aqm@ietf.org" , bloat Message-ID: <20161202224006.GA5065@sesse.net> References: <56F6A3AB-3A47-4178-BEFF-04E3DC23B039@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Operating-System: Linux 4.9.0-rc2 on a x86_64 User-Agent: Mutt/1.5.23 (2014-03-12) 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 22:40:11 -0000 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 */ -- Homepage: https://www.sesse.net/