added ECMP exercise for May 2016 P4 workshop

SIGCOMM_2015/source_routing/run_demo.sh

@@ -16,7 +16,7 @@
 
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 
-source $THIS_DIR/../env.sh
+source $THIS_DIR/../../env.sh
 
 P4C_BM_SCRIPT=$P4C_BM_PATH/p4c_bm/__main__.py
 
@@ -25,7 +25,9 @@ SWITCH_PATH=$BMV2_PATH/targets/simple_switch/simple_switch
 CLI_PATH=$BMV2_PATH/tools/runtime_CLI.py
 
 $P4C_BM_SCRIPT p4src/source_routing.p4 --json source_routing.json
+# This gives libtool the opportunity to "warm-up"
+sudo $SWITCH_PATH >/dev/null 2>&1
 sudo PYTHONPATH=$PYTHONPATH:$BMV2_PATH/mininet/ python topo.py \
-    --behavioral-exe $BMV2_PATH/targets/simple_switch/simple_switch \
+    --behavioral-exe $SWITCH_PATH \
     --json source_routing.json \
     --cli $CLI_PATH