Re: [UDT] UDT with congestion control

[Harald s. <sc...@rv...>]

Hmmmm....
i begin to understand what' s wrong with my measurement.
Where TCP congestion control is implemented only sender-side,
UDT uses control comunication between sender and receiver.
I had activated the CCC only at the sender side.

Perhaps i should have a deeper look at the documentation
befor asking the mailing list.... :-(


Bye
Harald



Am Freitag, den 03.03.2006, 08:21 +0100 schrieb Harald schwier:
> Hello Yunhong,
>=20
> Thank you for your answer.
> I have also tried the scalable, hstcp and BIC congestion contol
> algorithms as they are defined in cc.h.
> Every time i get a performance of 0.2 MB/s.
>=20
> For example, i activated scalable with:
> UDT::setsockopt(client,0,UDT_CC,newCCCFactory<CScalableTCP>,sizeof(CCCF=
actory<CScalableTCP>));
> Is there anything more to do? What may be the reason for the poor
> Performance?
>=20
> Thanks in advance,
> Harald
>=20
>=20
> > Hi, Harald,
> >=20
> > Once you uncomment the -DCUSTOM_CC option, the default UDT congestion=
=20
> > control algorithm will not be used any more.
> >=20
> > Default window size in UDT is 16 packets and it will not change unles=
s you=20
> > assign a new congestion control algorithm.
> >=20
> > Once you specify CTCP, you are using TCP's AIMD algorithm, which usua=
lly=20
> > does not work well for long distance links (you mentioned that RTT is=
=20
> > 100ms).
> >=20
> > Thanks
> > Yunhong
> >=20
> >=20
> > On Thu, 2 Mar 2006, Harald schwier wrote:
> >=20
> > > Hello,
> > > i'm doing some performance tests with UDT. Without changing
> > > any options, appclient shows 950 MB/s (1GB Ethernet, RTT about 100m=
s).
> > >
> > > After i uncomment the -DCUSTOM_CC compile option in ./src/Makefile
> > > and recompile the library the Performance goes down to 1.7 MB/s wit=
hout
> > > changing any Options in appclient.
> > >
> > > When i change the socket options with:
> > > UDT::setsockopt(client,0,UDT_CC,newCCCFactory<CTCP>,sizeof(CCCFacto=
ry<CTCP>));
> > > the performance goes down to 0.2 MB/s.
> > >
> > > UDT 2.3
> > > Compiled with: make -e os=3DLINUX arch=3DAMD64
> > >
> > > What may be the reason for the poor performance???
> > >
> > > Thanks in advance,
> > > Harald
> > >
> > >
> > >
> > >
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> Mit freundlichen Gr=C3=BC=C3=9Fen,
> Harald Schwier
>=20
>=20
Mit freundlichen Gr=C3=BC=C3=9Fen,
Harald Schwier


--=20
Dipl.-Ing. Harald Schwier          D-30159 Hannover
Lehrgebiet Rechnernetze            Schlosswender Str. 5
RRZN, Universit=C3=A4t Hannover         Tel: +49 (511) 762 7919081
Fachbereich Informatik