From owner-freebsd-net@FreeBSD.ORG Sun Aug 10 02:42:47 2014 Return-Path: <owner-freebsd-net@FreeBSD.ORG> Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 7C7329F5 for <freebsd-net@freebsd.org>; Sun, 10 Aug 2014 02:42:47 +0000 (UTC) Received: from mail-qa0-x232.google.com (mail-qa0-x232.google.com [IPv6:2607:f8b0:400d:c00::232]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 37BD727C1 for <freebsd-net@freebsd.org>; Sun, 10 Aug 2014 02:42:47 +0000 (UTC) Received: by mail-qa0-f50.google.com with SMTP id s7so6722366qap.23 for <freebsd-net@freebsd.org>; Sat, 09 Aug 2014 19:42:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=nSfRUkwt2/ofDoJUfmVKIyIsDadW8gYMfZt1/nxiG1w=; b=VFdOY+SeO9DsNNt0ggh5J6WLBCkGCzpRr8LTtkJpUUg9sidwp6ItUGTI5DPqN+Jf+l 7Petoj2Mv2C57kjRQCbDqgqI3E8NkPr/0IeHS6ch35tdZ7eQzsyUSD53HCYZbuC/+euv kgJYTtB1hME3H71po/92w+kQb+PcKzPB0cjwj09DlssuWEFlrtPitB1UeHbgB6NuKwDL gKeIVzQyU2hLeMWYGfkYqt6W+n2sER6FZEzqby79c6qeItRNcuX5Y8qTLTs5ngtxQoOx KagFBHI6DjovpjPEPSpNrzg/syj1agNalITJrWlvrx8SsW5W4bR+MG8cDrmPzRC0pgYd HKkA== MIME-Version: 1.0 X-Received: by 10.140.30.180 with SMTP id d49mr34369652qgd.63.1407638565872; Sat, 09 Aug 2014 19:42:45 -0700 (PDT) Received: by 10.224.137.71 with HTTP; Sat, 9 Aug 2014 19:42:45 -0700 (PDT) In-Reply-To: <20140810022350.GI83475@funkthat.com> References: <CAOENNMA_CiBDJc0kchzUbTcf_JBwTJPF=PdBAUB6FPo-KzYkeQ@mail.gmail.com> <20140809184232.GF83475@funkthat.com> <8AE1AC56-D52F-4F13-AAA3-BB96042B37DD@lurchi.franken.de> <20140809204500.GG83475@funkthat.com> <3F6BC212-4223-4AAC-8668-A27075DC55C2@lurchi.franken.de> <CAOENNMCPuiYS7LHwMfOczhZ4yisjGkpOmWzv2pcAoi9Hhzb7dw@mail.gmail.com> <20140810022350.GI83475@funkthat.com> Date: Sun, 10 Aug 2014 10:42:45 +0800 Message-ID: <CAOENNMB3=FZx5kSHVPDPBTtMKbmYJ=c_XNMcuYuoLPe=6U+kxg@mail.gmail.com> Subject: Re: A problem on TCP in High RTT Environment. From: Niu Zhixiong <kaiaixi@gmail.com> To: Niu Zhixiong <kaiaixi@gmail.com>, Michael Tuexen <Michael.Tuexen@lurchi.franken.de>, freebsd-net@freebsd.org, Bill Yuan <bycn82@gmail.com>, John-Mark Gurney <jmg@funkthat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net/> List-Post: <mailto:freebsd-net@freebsd.org> List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=subscribe> X-List-Received-Date: Sun, 10 Aug 2014 02:42:47 -0000 I am sure that wnd is about 2MB all the time. This is my latest capture, plz see Google Drive. In the latest test, TCP(0s-120s) is about 9Mbps and SCTP(0s-120s) is about 18Mbps. (The bandwidth(20Mbps) and delay(200ms) is set by dummynet) The SCTP and TCP are tested in same environment. =E2=80=8B sctp.pcapng.gz <https://docs.google.com/file/d/0By8sTL79ob4tYl9sM2V5a19iNVU/edit?usp=3Ddri= ve_web> =E2=80=8B=E2=80=8B tcp.pcapng.gz <https://docs.google.com/file/d/0By8sTL79ob4tV0NMR1FYLUQ3MWs/edit?usp=3Ddri= ve_web> =E2=80=8B Regards, Niu Zhixiong =EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF= =BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D kaiaixi@gmail.com On Sun, Aug 10, 2014 at 10:23 AM, John-Mark Gurney <jmg@funkthat.com> wrote= : > Niu Zhixiong wrote this message on Sun, Aug 10, 2014 at 10:12 +0800: > > During the TCP4 transmission. > > Proto Recv-Q Send-Q Local Address Foreign Address (stat= e) > > tcp4 0 2097346 10.0.10.2.13504 10.0.10.3.9000 > > ESTABLISHED > > Ok, so you are getting a full 2MB in there, and w/ that, you should > easily be saturating your pipe... > > The next thing would be to get a tcpdump, and take a look at the > window size.. Wireshark has lots of neat tools to make this analysis > easy... Another tool that is good is tcptrace.. It can output a > variety of different graphs that will help you track down, and see > what part of the system is the problem... > > You probably only need a few tens of seconds of the tcpdump... > > > On Sun, Aug 10, 2014 at 4:58 AM, Michael Tuexen < > > Michael.Tuexen@lurchi.franken.de> wrote: > > > > > > > > On 09 Aug 2014, at 22:45, John-Mark Gurney <jmg@funkthat.com> wrote: > > > > > > > Michael Tuexen wrote this message on Sat, Aug 09, 2014 at 21:51 > +0200: > > > >> > > > >> On 09 Aug 2014, at 20:42, John-Mark Gurney <jmg@funkthat.com> > wrote: > > > >> > > > >>> Niu Zhixiong wrote this message on Fri, Aug 08, 2014 at 20:34 > +0800: > > > >>>> Dear all, > > > >>>> > > > >>>> Last month, I send problems related to FTP/TCP in a high RTT > > > environment. > > > >>>> After that, I setup a simulation environment(Dummynet) to test T= CP > > > and SCTP > > > >>>> in high delay environment. After finishing the test, I can see > TCP is > > > >>>> always slower than SCTP. But, I think it is not possible. (Plz > see the > > > >>>> figure in the attachment). When the delay is 200ms(means > RTT=3D400ms). > > > >>>> Besides, the TCP is extremely slow. > > > >>>> > > > >>>> ALL BW=3D20Mbps, DELAY=3D 0 ~ 200MS, Packet LOSS =3D 0 (by dummy= net) > > > >>>> > > > >>>> This is my parameters: > > > >>>> FreeBSD vfreetest0 10.0-RELEASE FreeBSD 10.0-RELEASE #0: Thu Aug > 7 > > > >>>> 11:04:15 HKT 2014 > > > >>>> > > > >>>> sysctl net.inet.tcp > > > >>> > > > >>> [...] > > > >>> > > > >>>> net.inet.tcp.recvbuf_auto: 0 > > > >>> > > > >>> [...] > > > >>> > > > >>>> net.inet.tcp.sendbuf_auto: 0 > > > >>> > > > >>> Try enabling this... This should allow the buffer to grow large > enough > > > >>> to deal w/ the higher latency... > > > >>> > > > >>> Also, make sure your program isn't setting the recv buffer size a= s > that > > > >>> will disable the auto growing... > > > >> I think the program sets the buffer to 2MB, which it also does for > SCTP. > > > >> So having both statically at the same size makes sense for the > > > comparison. > > > >> I remember that there was a bug in the combination of LRO and > delayed > > > ACK, > > > >> which was fixed, but I don't remember it was fixed before 10.0... > > > > > > > > Sounds like disabling LRO and TSO would be a useful test to see if > that > > > > improves things... But hiren said that the fix made it, so... > > > > > > > >>> If you use netstat -a, you should be able to see the send-q on th= e > > > >>> sender grow as necessary... > > > > > > > > Also, getting the send-q output while it's running would let us kno= w > > > > if the buffer is getting to 2MB or not... > > > That is correct. Niu: Can you provide this? > > -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." >