Merge branch 'patches/linear_bw' of https://github.com/cdburkard/mininet into...

Merge branch 'patches/linear_bw' of https://github.com/cdburkard/mininet into cdburkard-patches/linear_bw

examples/linearbandwidth.py

@@ -28,6 +28,8 @@
 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
@@ -70,13 +72,20 @@ def linearBandwidthTest( lengths ):
     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 ] = []
-        net = Mininet( topo=topo, switch=Switch, controller=Controller, waitConnected=True )
+        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:

examples/test/test_linearbandwidth.py

@@ -21,7 +21,6 @@ def testLinearBandwidth( self ):
         while True:
             index = p.expect( opts, timeout=600 )
             if index == 0:
-                previous_bw = 10 ** 10 # 10 Gbits
                 count += 1
             elif index == 1:
                 n = int( p.match.group( 1 ) )
@@ -32,12 +31,15 @@ def testLinearBandwidth( self ):
                 elif unit[ 0 ] == 'M':
                     bw *= 10 ** 6
                 elif unit[ 0 ] == 'G':
-                    bw *= 10 ** 9
-                self.assertTrue( bw < previous_bw )
+                    bw *= 10 ** 9a
+                # check that we have a previous result to compare to
+                if n != 1:
+                    self.assertTrue( bw < previous_bw )
                 previous_bw = bw
             else:
                 break
 
+        # verify that we received results from at least one switch
         self.assertTrue( count > 0 )
 
 if __name__ == '__main__':