Useful Systemtap Scripts; Network; Network Profiling - Red Hat ENTERPRISE LINUX 5.4 - SYSTEMTAP BEGINNERS GUIDE Manual

Chapter 4.

Useful SystemTap Scripts

This chapter enumerates several SystemTap scripts you can use to monitor and investigate
different subsystems. All of these scripts are available at /usr/share/systemtap/testsuite/
systemtap.examples/ once you install the systemtap-testsuite RPM.

4.1. Network

The following sections showcase scripts that trace network-related functions and build a profile of
network activity.

4.1.1. Network Profiling

This section describes how to profile network activity.
network traffic each process is generating on a machine.
nettop.stp
#! /usr/bin/env stap
global ifxmit, ifrecv
global ifmerged
probe netdev.transmit
{
ifxmit[pid(), dev_name, execname(), uid()] <<< length
}
probe netdev.receive
{
ifrecv[pid(), dev_name, execname(), uid()] <<< length
}
function print_activity()
{
printf("%5s %5s %-7s %7s %7s %7s %7s %-15s\n",
"PID", "UID", "DEV", "XMIT_PK", "RECV_PK",
"XMIT_KB", "RECV_KB", "COMMAND")
foreach ([pid, dev, exec, uid] in ifrecv) {
ifmerged[pid, dev, exec, uid] += @count(ifrecv[pid,dev,exec,uid]);
}
foreach ([pid, dev, exec, uid] in ifxmit) {
ifmerged[pid, dev, exec, uid] += @count(ifxmit[pid,dev,exec,uid]);
}
foreach ([pid, dev, exec, uid] in ifmerged-) {
n_xmit = @count(ifxmit[pid, dev, exec, uid])
n_recv = @count(ifrecv[pid, dev, exec, uid])
printf("%5d %5d %-7s %7d %7d %7d %7d %-15s\n",
pid, uid, dev, n_xmit, n_recv,
n_xmit ? @sum(ifxmit[pid, dev, exec, uid])/1024 : 0,
n_recv ? @sum(ifrecv[pid, dev, exec, uid])/1024 : 0,
exec)
}
print("\n")
nettop.stp
provides a glimpse into how much
27