Date: Sun, 10 Aug 2014 10:42:45 +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: <CAOENNMB3=FZx5kSHVPDPBTtMKbmYJ=c_XNMcuYuoLPe=6U%2Bkxg@mail.gmail.com> 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>
next in thread | previous in thread | raw e-mail | index | archive | help
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." >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAOENNMB3=FZx5kSHVPDPBTtMKbmYJ=c_XNMcuYuoLPe=6U%2Bkxg>