From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x231.google.com (mail-oi0-x231.google.com [IPv6:2607:f8b0:4003:c06::231]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id AFE6E21F38A for ; Wed, 13 May 2015 16:26:06 -0700 (PDT) Received: by oica37 with SMTP id a37so43731775oic.0 for ; Wed, 13 May 2015 16:26:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=JPsOXdSHzzMVZ+hpmsafPrDwY+gRjB+jQCnrM+LrVZw=; b=wyS/k+TCdBwGVgfE7hEi8DJxW7gBs/gyFFO65KjgmSock9f2hn7/trIrz7PjKFM14y A7R34ZoHzXWGHUabzNFtJ25PlrQp8hz0kItRmN5PCon7EnzWX9nRcZX3pwjXKqMeNwxm jq3a+jbd0kSiTPh5xg/IKtj4ixJwXqn0B6TCWL34GC8z0dr1TuznCK65WhEg72Cl4lPn TALevJ5Qsx3JbaQNYlmbzlr/Dcfvb86R6+GznJzMeNu1rT119/WWeSqZ9/X3N8Bds4ln sDgX02D4cH6RbzRSN/mQ7FOhZ5aSzrRhuzYORtogfdrvLLEB5p8Sl4Ghx13w/3h02Y4Q V2Tw== MIME-Version: 1.0 X-Received: by 10.202.223.131 with SMTP id w125mr1034705oig.108.1431559565008; Wed, 13 May 2015 16:26:05 -0700 (PDT) Received: by 10.202.71.139 with HTTP; Wed, 13 May 2015 16:26:04 -0700 (PDT) Date: Wed, 13 May 2015 16:26:04 -0700 Message-ID: From: Dave Taht To: renaud sallantin , bloat Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Bloat] initial spreading patch? 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: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 X-List-Received-Date: Wed, 13 May 2015 23:26:36 -0000 dear renaud: my take on this was that we should measure this from a couple RTT samples in the case of SSL, rather than a fixed qty, although the syn/synack pair might be good enough for many purposes. that said, do you have the simple patch lying around? the dslreports.com tests show the carnage when 8 or 24 flows start simultaneously. I know that those that need TSO for their short transactions will hate it but in my case what I am seeing on an uplink (10mbit) is a giant IW10 GRO packet arrives in the latest routers (where we do not break it up, presently, back into packets), so I would like to fiddle with the concept more. On Fri, Mar 21, 2014 at 8:53 AM, renaud sallantin wrote: > For our tests, we needed to adjust the "tcp_initial_quantum" in the FQ, > but as you said, it is just a FQ parameter. > > The "patch" we added, and once again, it was just a few lines, enabled t= o > set, via a sysctl parameter, the initial pacing value, regardless of the > RTT. > This can be valuable for different reasons: > o In case of long RTT, not set the pacing value is going to introdu= ce > an un-necessary delay > (we aims to use this mechanism for satcom, so the delay could be greater > than 500ms) > o In case of a wrong RTT measurement, i.e. an RTT measurement that = is > higher that the real RTT (because of congestion for example), you are go= ing > to have a wrong pacing evaluation... > > and finally, for experimental purpose, be able to change the initial paci= ng > value could be very interesting > > > 2014-03-21 16:06 GMT+01:00 Eric Dumazet : >> >> On Fri, 2014-03-21 at 09:15 +0100, renaud sallantin wrote: >> >> > >> > FQ/pacing enables to do a lot of things, >> > and as I already said, it could be used to easily implement the >> > Initial Spreading. >> > (we did it and it' s just a few lines to add, and a couple of >> > parameters to change) >> > >> > >> > But for the moment, FQ/Pacing sends the IW in one burst (up to 10 >> > segments). >> > >> >> This is not true. This depends on RTT and your qdisc parameters. >> >> Whole point of TSO autosizing is to make all this stuff automatic. >> >> Here is the tcpdump output for a 10ms RTT, which is quite standard. >> >> You can see 5 packets are sent, with a delay of more than 1 ms. >> >> 07:58:52.616379 IP 10.246.11.51.39905 > 10.246.11.52.41276: S >> 2187811646:2187811646(0) win 29200 >> 07:58:52.626575 IP 10.246.11.52.41276 > 10.246.11.51.39905: S >> 81785763:81785763(0) ack 2187811647 win 29200 > 1460,nop,nop,sackOK,nop,wscale 7> >> 07:58:52.626642 IP 10.246.11.51.39905 > 10.246.11.52.41276: . ack 1 win >> 457 >> 07:58:52.626671 IP 10.246.11.51.39905 > 10.246.11.52.41276: . 1:2921(292= 0) >> ack 1 win 457 >> 07:58:52.627740 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 2921:5841(2920) ack 1 win 457 >> 07:58:52.628815 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 5841:8761(2920) ack 1 win 457 >> 07:58:52.629946 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 8761:11681(2920) ack 1 win 457 >> 07:58:52.631054 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 11681:14601(2920) ack 1 win 457 >> 07:58:52.637147 IP 10.246.11.52.41276 > 10.246.11.51.39905: . ack 2921 w= in >> 274 >> 07:58:52.637207 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 14601:17521(2920) ack 1 win 457 >> 07:58:52.638117 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 17521:20441(2920) ack 1 win 457 >> 07:58:52.638114 IP 10.246.11.52.41276 > 10.246.11.51.39905: . ack 5841 w= in >> 320 >> 07:58:52.639011 IP 10.246.11.51.39905 > 10.246.11.52.41276: . >> 20441:23361(2920) ack 1 win 457 >> >> >> You also can tune /proc/sys/net/ipv4/tcp_min_tso_segs from 2 to 1 if you >> really want... >> >> No kernel patches needed... >> >> >> > --=20 Dave T=C3=A4ht Open Networking needs **Open Source Hardware** https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67