From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [129.241.93.19]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id B7B2A200B1E for ; Fri, 6 Apr 2012 14:37:33 -0700 (PDT) Received: from pannekake.samfundet.no ([2001:700:300:1800::dddd] ident=unknown) by cassarossa.samfundet.no with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1SGGqU-00061K-FC for bloat@lists.bufferbloat.net; Fri, 06 Apr 2012 23:37:26 +0200 Received: from sesse by pannekake.samfundet.no with local (Exim 4.72) (envelope-from ) id 1SGGqT-0003uJ-Kp for bloat@lists.bufferbloat.net; Fri, 06 Apr 2012 23:37:25 +0200 Date: Fri, 6 Apr 2012 23:37:25 +0200 From: "Steinar H. Gunderson" To: bloat@lists.bufferbloat.net Message-ID: <20120406213725.GA12641@uio.no> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Operating-System: Linux 3.3.0 on a x86_64 User-Agent: Mutt/1.5.20 (2009-06-14) Subject: [Bloat] Best practices for paced TCP on 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: Fri, 06 Apr 2012 21:37:34 -0000 Hi, This is only related to bloat, so bear with me if it's not 100% on-topic; I guess the list is about the best place on the Internet to get a reasonble answer for this anyway :-) Long story short, I have a Linux box (running 3.2.0 or so) with a 10Gbit/sec interface, streaming a large amount of video streams to external users, at 1Mbit/sec, 3Mbit/sec or 5Mbit/sec (different values). Unfortunately, even though there is no congestion in _our_ network (we have 190 Gbit/sec free!), some users are complaining that they can't keep the stream up. My guess is that this is because at 10Gbit/sec, we are crazy bursty, and somewhere along the line, there will be devices doing down conversion without enough buffers (for instance, I've seen drop behavior on Cisco 2960-S in a very real ISP network on 10->1 Gbit/sec down conversion, and I doubt it's the worst offender here). Is there anything I can do about this on my end? I looked around for paced TCP implementations, but couldn't find anything current. Can I somehow shape each TCP stream to 10Mbit/sec or so each with a combination of SFQ and TBF? (SFQRED?) I'm not very well versed in tc, so anything practical would be very much appreciated. Bonus points if we won't have to patch the kernel. /* Steinar */ -- Homepage: http://www.sesse.net/