Question

I’m trying to plot the TCP congestion window and the slow start threshold using iperf and the tcp_probe module. I do exactly what is told here:

to obtain the data:

modprobe tcp_probe port=5001

chmod 444 /proc/net/tcpprobe

cat /proc/net/tcpprobe >/tmp/tcpprobe.out &

TCPCAP=$!

iperf -i 10 -t 100 -c receiver

kill $TCPCAP

Oops!

/tmp/tcpprobe.out is empty 🙁

This is Ubuntu 11.04 x86

and already tried the same on Ubuntu 11.04 x64

Any suggestions?

Answer 1

I was having the same problem. What worked for me was:

modprobe -r tcp_probe

sudo modprobe tcp_probe port=5002 full=1

sudo chmod 444 /proc/net/tcpprobe

cat /proc/net/tcpprobe > /tmp/tcpprobe.out &

TCPCAP=$!

iperf -c <servers IP address here> -p 5002 -t 100 -i 1

sudo kill $TCPCAP

See iperf parameters to check if those (-t 100 -i 1) are what you need by typing:

man iperf