Networking Monitoring – Linux Tool to Monitor Bandwidth Consumption of a Specific Process (PID)

something to get you started (just in case you want to write it yourself):

#!/bin/bash
#
# usage: bwmon PID

IN=0; OUT=0; TIME=0

get_traffic() {
    t=`awk '/eth0:/ { printf("%s,%d,%d\n",strftime("%s"),$2,$10); }' < /proc/$1/net/dev`
    IN=${t#*,}; IN=${IN%,*}
    OUT=${t##*,};
    TIME=${t%%,*};
}

get_traffic $1
while true
do
    _IN=$IN; _OUT=$OUT; _TIME=$TIME
    get_traffic $1
    echo "$TIME,$(( $TIME - $_TIME )),$IN,$(( $IN - $_IN )),$OUT,$(( $OUT - $_OUT))"
    sleep 1
done

comments:

• checks only eth0
• checks every 1 second
• works only under linux, but other unixes work similar (procfs or whatever)
• output could be stored into a sqlite.db with stat --printf="%N\n" /proc/PID/exe | cut -d ' ' -f 3

You know you already have that with ifconfig right?

Ifconfig keeps counters about your incomming and outgoing bandwidth on each interface by default. Usually you can't reset counters except rebooting (with a few exceptions)

From console you can easily leave a cron running each three days and saving results to a file for later check. Something like this:

date >> ~/bw.log && ifconfig eth0|grep byte >> ~/bw.log

Will produce this kind of output per run on the file bw.log at users home.

Thu Oct 18 03:44:05 UTC 2012
      RX bytes:414910161 (395.6 MiB)  TX bytes:68632105 (65.4 MiB)

My two cents...