Added --test-payload option

flent/runners.py

@@ -983,6 +983,7 @@ def check(self):
         args.setdefault('send_size',
                         self.settings.SEND_SIZE[0]
                         if self.settings.SEND_SIZE else "")
+        args.setdefault('test_payload', self.settings.TEST_PAYLOAD)
 
         if self.settings.SWAP_UPDOWN:
             if self.test == 'TCP_STREAM':
@@ -1022,12 +1023,19 @@ def check(self):
                 netperf['-e'] = True
 
             try:
-                # Sanity check; is /dev/urandom readable? If so, use it to
+                # If --test-payload option is specified, use data from that file
+                # else use the default value /dev/urandom. 
+                fill_file = args['test_payload']
+                # Sanity check; is /dev/urandom or the custom file readable? If so, use it to
                 # pre-fill netperf's buffers
-                self.run_simple(['dd', 'if=/dev/urandom', 'of=/dev/null', 'bs=1', 'count=1'], errmsg="Err")
-                netperf['buffer'] = '-F /dev/urandom'
+                self.run_simple(['dd', 'if='+fill_file, 'of=/dev/null', 'bs=1', 'count=1'], errmsg="Err")
+                netperf['buffer'] = '-F '+fill_file
             except RunnerCheckError:
-                netperf['buffer'] = ''
+                if(fill_file == '/dev/urandom'):
+                    netperf['buffer'] = ''
+                else:
+                    # If the custom file is not readable, fail noisily
+                    raise RunnerCheckError("The specified test payload file does not exist or is not readable.")
 
             if not self.remote_host:
                 # only cache values if we're not executing the checks on a

flent/settings.py

@@ -378,6 +378,12 @@ def __call__(self, parser, namespace, values, option_string=None):
     "to decrease the socket buffer size. Can be specified multiple times, "
     "with each value corresponding to a stream of a test.")
 
+test_group.add_argument(
+    "--test-payload",
+    action="store", type=unicode, dest="TEST_PAYLOAD", default='/dev/urandom',
+    help="Path to file containing payload to pre-fill the netperf buffers with "
+    "defaults to randomised payload")
+
 test_group.add_argument(
     "--test-parameter",
     action=Update, type=keyval, dest="TEST_PARAMETERS", metavar='key=value',

flent/testenv.py

@@ -57,7 +57,7 @@
 # in the code below
 STREAM_CONFIG_PARAM_NAMES = ['label', 'ping_label', 'marking',
                              'control_host', 'local_bind', 'cc_algo',
-                             'udp_bandwidth', 'udp_pktsize', 'send_size']
+                             'udp_bandwidth', 'udp_pktsize', 'send_size', 'test_payload']
 
 # Mapping of test parameters that will be picked up from the global settings if
 # they are not set