From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x236.google.com (mail-pa0-x236.google.com [IPv6:2607:f8b0:400e:c03::236]) (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 A30BE21F559 for ; Thu, 11 Sep 2014 14:13:21 -0700 (PDT) Received: by mail-pa0-f54.google.com with SMTP id lj1so11533272pab.27 for ; Thu, 11 Sep 2014 14:13:20 -0700 (PDT) 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 :content-type:content-transfer-encoding:mime-version; bh=LWALpqu+V2DL9JOhtBX86+PpgnxUO4UvZ8rRx82opGk=; b=cuL/HgkE4o847iyhhGTpg+U69EYt78rkP7IfXXJ5KAKJi3B/26e9fgcSlZqyYKE+dd Ch11gCChbIT+Xhf0t2j0fkZfX7EMDYlZJCYv3N2Y5Ww6ZcfEoWu/uJJQ9iMSgzVuNPmn +PACMxOjaynKbqaYUX3iidn5aHQ/U+43bsT5SqDSni1HW9EC42ZhitY/yswGfKcBcFj9 rw9LQoKhYIUzKJ0gv8e0qR3Ft1HlqH0LCeWxR5P4JR6iZSI7dtyL5F7Ptf6GwiBk+lfh U1A6Ax/Do8MWxhQae3OAfEk0wTHNd4b/s1qGt8gmZZdojAaaswJA21IPsjC4W1fkyXWR M2gA== X-Received: by 10.67.12.175 with SMTP id er15mr5023771pad.143.1410470000796; Thu, 11 Sep 2014 14:13:20 -0700 (PDT) Received: from ?IPv6:2620:0:1000:3e02:64d0:ed57:c918:d391? ([2620:0:1000:3e02:64d0:ed57:c918:d391]) by mx.google.com with ESMTPSA id ta6sm2033083pac.14.2014.09.11.14.13.20 for (version=SSLv3 cipher=RC4-SHA bits=128/128); Thu, 11 Sep 2014 14:13:20 -0700 (PDT) Message-ID: <1410469999.7106.58.camel@edumazet-glaptop2.roam.corp.google.com> From: Eric Dumazet To: "Steinar H. Gunderson" Date: Thu, 11 Sep 2014 14:13:19 -0700 In-Reply-To: <20140911174037.GA22515@sesse.net> References: <000001cfc609$697feb30$3c7fc190$@duckware.com> <1410455146.7106.55.camel@edumazet-glaptop2.roam.corp.google.com> <20140911174037.GA22515@sesse.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] What is wrong with Microsoft's receive window auto-tuning? 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: Thu, 11 Sep 2014 21:13:49 -0000 On Thu, 2014-09-11 at 19:40 +0200, Steinar H. Gunderson wrote: > On Thu, Sep 11, 2014 at 10:05:46AM -0700, Eric Dumazet wrote: > >> Is anyone aware of any research either pointing out how their tuning > >> algorithm works, or of known bugs/problems with the algorithm? > > How BDP suggests a receive window of 750k ? > > > > If BDP _is_ 750k, then 3.8 MB receive window is not insane, it depends > > on the amount of drops and how fast you want to recover from drops. > > If it helps, I've seen problems in Linux' auto-tuning as well, so this is > seemingly a hard problem :-) Right. Note we did some changes in the DRS code in latest linux versions (3.13 If I remember well) http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b0983d3c9b132c33b6fb2e28d157a1edc18a173c