lantz
128 lines
3.9 KiB
Python
Executable File
128 lines
3.9 KiB
Python
Executable File
#!/usr/bin/python
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"""
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Test bandwidth (using iperf) on linear networks of varying size,
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using both kernel and user datapaths.
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We construct a network of N hosts and N-1 switches, connected as follows:
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h1 <-> s1 <-> s2 .. sN-1
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h2 h3 hN
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WARNING: by default, the reference controller only supports 16
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switches, so this test WILL NOT WORK unless you have recompiled
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your controller to support 100 switches (or more.)
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In addition to testing the bandwidth across varying numbers
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of switches, this example demonstrates:
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- creating a custom topology, LinearTestTopo
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- using the ping() and iperf() tests from Mininet()
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- testing both the kernel and user switches
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"""
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import sys
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from functools import partial
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from mininet.net import Mininet
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from mininet.node import UserSwitch, OVSKernelSwitch, Controller
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from mininet.topo import Topo
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from mininet.log import lg, info
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from mininet.util import irange, quietRun
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from mininet.link import TCLink
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flush = sys.stdout.flush
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class LinearTestTopo( Topo ):
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"Topology for a string of N hosts and N-1 switches."
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# pylint: disable=arguments-differ
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def build( self, N, **params ):
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# Create switches and hosts
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hosts = [ self.addHost( 'h%s' % h )
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for h in irange( 1, N ) ]
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switches = [ self.addSwitch( 's%s' % s )
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for s in irange( 1, N - 1 ) ]
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# Wire up switches
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last = None
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for switch in switches:
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if last:
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self.addLink( last, switch )
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last = switch
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# Wire up hosts
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self.addLink( hosts[ 0 ], switches[ 0 ] )
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for host, switch in zip( hosts[ 1: ], switches ):
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self.addLink( host, switch )
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def linearBandwidthTest( lengths ):
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"Check bandwidth at various lengths along a switch chain."
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results = {}
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switchCount = max( lengths )
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hostCount = switchCount + 1
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switches = { 'reference user': UserSwitch,
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'Open vSwitch kernel': OVSKernelSwitch }
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# UserSwitch is horribly slow with recent kernels.
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# We can reinstate it once its performance is fixed
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del switches[ 'reference user' ]
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topo = LinearTestTopo( hostCount )
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# Select TCP Reno
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output = quietRun( 'sysctl -w net.ipv4.tcp_congestion_control=reno' )
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assert 'reno' in output
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for datapath in switches:
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info( "*** testing", datapath, "datapath\n" )
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Switch = switches[ datapath ]
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results[ datapath ] = []
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link = partial( TCLink, delay='30ms', bw=100 )
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net = Mininet( topo=topo, switch=Switch,
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controller=Controller, link=link,
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waitConnected=True )
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net.start()
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info( "*** testing basic connectivity\n" )
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for n in lengths:
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net.ping( [ net.hosts[ 0 ], net.hosts[ n ] ] )
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info( "*** testing bandwidth\n" )
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for n in lengths:
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src, dst = net.hosts[ 0 ], net.hosts[ n ]
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# Try to prime the pump to reduce PACKET_INs during test
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# since the reference controller is reactive
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src.cmd( 'telnet', dst.IP(), '5001' )
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info( "testing", src.name, "<->", dst.name, '\n' )
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# serverbw = received; _clientbw = buffered
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serverbw, _clientbw = net.iperf( [ src, dst ], seconds=5 )
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info( serverbw, '\n' )
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flush()
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results[ datapath ] += [ ( n, serverbw ) ]
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net.stop()
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for datapath in switches:
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info( "\n*** Linear network results for", datapath, "datapath:\n" )
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result = results[ datapath ]
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info( "SwitchCount\tiperf Results\n" )
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for switchCount, serverbw in result:
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info( switchCount, '\t\t' )
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info( serverbw, '\n' )
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info( '\n')
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info( '\n' )
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if __name__ == '__main__':
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lg.setLogLevel( 'info' )
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sizes = [ 1, 2, 3, 4 ]
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info( "*** Running linearBandwidthTest", sizes, '\n' )
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linearBandwidthTest( sizes )
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