Files
mininet/examples/linearbandwidth.py
T
Bob Lantz f6de358b06 Try to prime the pump to avoid PACKET_INs during iperf test
Background: the reference controller is reactive and installs exact
match rules. By attempting to start a telnet session we make sure that
the ARP caches and TCP flow rules are set up (in one direction at
least) before the test starts.

This is intended to help with #413
2014-10-31 15:06:15 -07:00

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3.8 KiB
Python
Executable File

#!/usr/bin/python
"""
Test bandwidth (using iperf) on linear networks of varying size,
using both kernel and user datapaths.
We construct a network of N hosts and N-1 switches, connected as follows:
h1 <-> s1 <-> s2 .. sN-1
| | |
h2 h3 hN
WARNING: by default, the reference controller only supports 16
switches, so this test WILL NOT WORK unless you have recompiled
your controller to support 100 switches (or more.)
In addition to testing the bandwidth across varying numbers
of switches, this example demonstrates:
- creating a custom topology, LinearTestTopo
- using the ping() and iperf() tests from Mininet()
- testing both the kernel and user switches
"""
from mininet.net import Mininet
from mininet.node import UserSwitch, OVSKernelSwitch, Controller
from mininet.topo import Topo
from mininet.log import lg
from mininet.util import irange
from mininet.link import TCLink
from functools import partial
import sys
flush = sys.stdout.flush
class LinearTestTopo( Topo ):
"Topology for a string of N hosts and N-1 switches."
def __init__( self, N, **params ):
# Initialize topology
Topo.__init__( self, **params )
# Create switches and hosts
hosts = [ self.addHost( 'h%s' % h )
for h in irange( 1, N ) ]
switches = [ self.addSwitch( 's%s' % s )
for s in irange( 1, N - 1 ) ]
# Wire up switches
last = None
for switch in switches:
if last:
self.addLink( last, switch )
last = switch
# Wire up hosts
self.addLink( hosts[ 0 ], switches[ 0 ] )
for host, switch in zip( hosts[ 1: ], switches ):
self.addLink( host, switch )
def linearBandwidthTest( lengths ):
"Check bandwidth at various lengths along a switch chain."
results = {}
switchCount = max( lengths )
hostCount = switchCount + 1
switches = { 'reference user': UserSwitch,
'Open vSwitch kernel': OVSKernelSwitch }
# UserSwitch is horribly slow with recent kernels.
# We can reinstate it once its performance is fixed
del switches[ 'reference user' ]
topo = LinearTestTopo( hostCount )
for datapath in switches.keys():
print "*** testing", datapath, "datapath"
Switch = switches[ datapath ]
results[ datapath ] = []
link = partial( TCLink, delay='1ms' )
net = Mininet( topo=topo, switch=Switch,
controller=Controller, waitConnected=True,
link=link )
net.start()
print "*** testing basic connectivity"
for n in lengths:
net.ping( [ net.hosts[ 0 ], net.hosts[ n ] ] )
print "*** testing bandwidth"
for n in lengths:
src, dst = net.hosts[ 0 ], net.hosts[ n ]
# Try to prime the pump to reduce PACKET_INs during test
# since the reference controller is reactive
src.cmd( 'telnet', dst.IP(), '5001' )
print "testing", src.name, "<->", dst.name,
bandwidth = net.iperf( [ src, dst ] )
print bandwidth
flush()
results[ datapath ] += [ ( n, bandwidth ) ]
net.stop()
for datapath in switches.keys():
print
print "*** Linear network results for", datapath, "datapath:"
print
result = results[ datapath ]
print "SwitchCount\tiperf Results"
for switchCount, bandwidth in result:
print switchCount, '\t\t',
print bandwidth[ 0 ], 'server, ', bandwidth[ 1 ], 'client'
print
print
if __name__ == '__main__':
lg.setLogLevel( 'info' )
sizes = [ 1, 10, 20, 40, 60, 80, 100 ]
print "*** Running linearBandwidthTest", sizes
linearBandwidthTest( sizes )