Date: Sun, 10 Aug 2014 10:50:49 +0800 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> Subject: Re: A problem on TCP in High RTT Environment. Message-ID: <CAOENNMARg36KH1Y%2B0wG8pd7sSf8XKnMf6g790_KiKaj3Mdwyjw@mail.gmail.com> In-Reply-To: <CAOENNMB3=FZx5kSHVPDPBTtMKbmYJ=c_XNMcuYuoLPe=6U%2Bkxg@mail.gmail.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> <CAOENNMB3=FZx5kSHVPDPBTtMKbmYJ=c_XNMcuYuoLPe=6U%2Bkxg@mail.gmail.com>
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I am sorry that I upload a WRONG SCTP capture. But, the throughput is same. SCTP is double than TCP, about 18Mbps. =E2=80=8B sctp_2.pcapng.gz <https://docs.google.com/file/d/0By8sTL79ob4tMlh4WDlTSndHX0k/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 10:42 AM, Niu Zhixiong <kaiaixi@gmail.com> wrote: > 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 abou= t > 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=3Dd= rive_web> > =E2=80=8B=E2=80=8B > tcp.pcapng.gz > <https://docs.google.com/file/d/0By8sTL79ob4tV0NMR1FYLUQ3MWs/edit?usp=3Dd= rive_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 >> (state) >> > 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 >> TCP >> > > 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 dumm= ynet) >> > > >>>> >> > > >>>> This is my parameters: >> > > >>>> FreeBSD vfreetest0 10.0-RELEASE FreeBSD 10.0-RELEASE #0: Thu Au= g >> 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 >> as that >> > > >>> will disable the auto growing... >> > > >> I think the program sets the buffer to 2MB, which it also does fo= r >> 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 t= he >> > > >>> sender grow as necessary... >> > > > >> > > > Also, getting the send-q output while it's running would let us kn= ow >> > > > 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." >> > >
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