#!/usr/bin/python

"""

cpu.py: test iperf bandwidth for varying cpu limits

"""

from mininet.net import Mininet

from mininet.node import CPULimitedHost

from mininet.topolib import TreeTopo

from mininet.util import custom, waitListening

from mininet.log import setLogLevel, info

def bwtest( cpuLimits, period_us=100000, seconds=5 ):

"""Example/test of link and CPU bandwidth limits

cpu: cpu limit as fraction of overall CPU time"""

topo = TreeTopo( depth=1, fanout=2 )

results = {}

for sched in 'rt', 'cfs':

print '*** Testing with', sched, 'bandwidth limiting'

for cpu in cpuLimits:

host = custom( CPULimitedHost, sched=sched,

period_us=period_us,

cpu=cpu )

try:

net = Mininet( topo=topo, host=host )

# pylint: disable=bare-except

except:

info( '*** Skipping host %s\n' % sched )

break

net.start()

net.pingAll()

hosts = [ net.getNodeByName( h ) for h in topo.hosts() ]

client, server = hosts[ 0 ], hosts[ -1 ]

server.cmd( 'iperf -s -p 5001 &' )

waitListening( client, server, 5001 )

result = client.cmd( 'iperf -yc -t %s -c %s' % (

seconds, server.IP() ) ).split( ',' )

bps = float( result[ -1 ] )

server.cmdPrint( 'kill %iperf' )

net.stop()

updated = results.get( sched, [] )

updated += [ ( cpu, bps ) ]

results[ sched ] = updated

return results

def dump( results ):

"Dump results"

fmt = '%s\t%s\t%s'

print

print fmt % ( 'sched', 'cpu', 'client MB/s' )

print

for sched in sorted( results.keys() ):

entries = results[ sched ]

for cpu, bps in entries:

pct = '%.2f%%' % ( cpu * 100 )

mbps = bps / 1e6

print fmt % ( sched, pct, mbps )

if __name__ == '__main__':

setLogLevel( 'info' )

limits = [ .45, .4, .3, .2, .1 ]

out = bwtest( limits )

dump( out )