experiments: enable/disable pcap file in run script

experiments/run.py

@@ -52,6 +52,8 @@ parser.add_argument('--force', action='store_const', const=True, default=False,
 parser.add_argument('--verbose', action='store_const', const=True,
         default=False,
         help='Verbose output')
+parser.add_argument('--pcap', action='store_const', const=True, default=False,
+        help='Dump pcap file (if supported by simulator)')
 
 g_env = parser.add_argument_group('Environment')
 g_env.add_argument('--repo', metavar='DIR', type=str,
@@ -104,6 +106,9 @@ def add_exp(e, run, prereq, create_cp, restore_cp):
     env = exp.ExpEnv(args.repo, workdir, cpdir)
     env.create_cp = create_cp
     env.restore_cp = restore_cp
+    env.pcap_file = ''
+    if args.pcap:
+        env.pcap_file = workdir+'/pcap'
 
     run = runtime.Run(e, run, env, outpath, prereq)
     rt.add_run(run)

experiments/simbricks/simulators.py

@@ -248,6 +248,8 @@ class SwitchNet(NetSim):
     def run_cmd(self, env):
         cmd = env.repodir + '/sims/net/switch/net_switch'
         cmd += f' -m {self.sync_mode} -S {self.sync_period} -E {self.eth_latency}'
+        if len(env.pcap_file) > 0:
+            cmd += ' -p ' + env.pcap_file
         for n in self.nics:
             cmd += ' -s ' + env.nic_eth_path(n)
         return cmd