NFVBENCH-79 TRex latency stats requires at least 18B payload size

Change-Id: I4add34e853d5b5a37efc877eb183a1fdc622d78a
Signed-off-by: Kerim Gokarslan <kgokarsl@cisco.com>
(cherry picked from commit 5d582aada32e1c5f43601015660b7936013f5b30)

3 files changed, 29 insertions, 15 deletions

diff --git a/nfvbench/nfvbench.py b/nfvbench/nfvbench.py
index 5899652..5e2de76 100644
--- a/nfvbench/nfvbench.py
+++ b/nfvbench/nfvbench.py
@@ -91,7 +91,19 @@ class NFVBench(object):
         try:
             self.update_config(opts)
             self.setup()
-
+            new_frame_sizes = []
+            min_packet_size = "68" if self.config.vlan_tagging else "64"
+            for frame_size in self.config.frame_sizes:
+                try:
+                    if int(frame_size) < int(min_packet_size):
+                        new_frame_sizes.append(min_packet_size)
+                        LOG.info("Adjusting frame size %s Bytes to minimum size %s Bytes due to "
+                                 + "traffic generator restriction", frame_size, min_packet_size)
+                    else:
+                        new_frame_sizes.append(frame_size)
+                except ValueError:
+                    new_frame_sizes.append(frame_size)
+            self.config.frame_sizes = tuple(new_frame_sizes)
             result = {
                 "date": datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S'),
                 "nfvbench_version": __version__,
diff --git a/nfvbench/traffic_gen/traffic_base.py b/nfvbench/traffic_gen/traffic_base.py
index c2ac8d0..81537b3 100644
--- a/nfvbench/traffic_gen/traffic_base.py
+++ b/nfvbench/traffic_gen/traffic_base.py
@@ -23,19 +23,12 @@ class TrafficGeneratorException(Exception):
 
 
 class AbstractTrafficGenerator(object):
-    # src_mac (6) + dst_mac (6) + mac_type (2) + frame_check (4) = 18
-    l2_header_size = 18
-
-    imix_l2_sizes = [64, 594, 1518]
-    imix_l3_sizes = [size - l2_header_size for size in imix_l2_sizes]
-    imix_ratios = [7, 4, 1]
-    imix_avg_l2_size = sum(
-        [1.0 * imix[0] * imix[1] for imix in zip(imix_l2_sizes, imix_ratios)]) / sum(imix_ratios)
-
-    traffic_utils.imix_avg_l2_size = imix_avg_l2_size
-
     def __init__(self, config):
         self.config = config
+        self.imix_l2_sizes = [64, 594, 1518]
+        self.imix_ratios = [7, 4, 1]
+        self.imix_avg_l2_size = 0
+        self.adjust_imix_min_size(64)
 
     @abc.abstractmethod
     def get_version(self):
@@ -96,3 +89,11 @@ class AbstractTrafficGenerator(object):
     def cleanup(self):
         # Must be implemented by sub classes
         return None
+
+    def adjust_imix_min_size(self, min_size):
+        # assume the min size is always the first entry
+        self.imix_l2_sizes[0] = min_size
+        self.imix_avg_l2_size = sum(
+            [1.0 * imix[0] * imix[1] for imix in zip(self.imix_l2_sizes, self.imix_ratios)]) / sum(
+                self.imix_ratios)
+        traffic_utils.imix_avg_l2_size = self.imix_avg_l2_size
diff --git a/nfvbench/traffic_gen/trex.py b/nfvbench/traffic_gen/trex.py
index 4c9f492..7d64f0f 100644
--- a/nfvbench/traffic_gen/trex.py
+++ b/nfvbench/traffic_gen/trex.py
@@ -142,14 +142,13 @@ class TRex(AbstractTrafficGenerator):
     def create_pkt(self, stream_cfg, l2frame_size):
 
         pkt_base = Ether(src=stream_cfg['mac_src'], dst=stream_cfg['mac_dst'])
-        # TRex requires minimum payload size 16B
         if stream_cfg['vlan_tag'] is not None:
             # 50 = 14 (Ethernet II) + 4 (Vlan tag) + 4 (CRC Checksum) + 20 (IPv4) + 8 (UDP)
             pkt_base /= Dot1Q(vlan=stream_cfg['vlan_tag'])
-            l2payload_size = max(max(64, int(l2frame_size)) - 50, 16)
+            l2payload_size = int(l2frame_size) - 50
         else:
             # 46 = 14 (Ethernet II) + 4 (CRC Checksum) + 20 (IPv4) + 8 (UDP)
-            l2payload_size = max(max(64, int(l2frame_size)) - 46, 16)
+            l2payload_size = int(l2frame_size) - 46
         payload = 'x' * l2payload_size
         udp_args = {}
         if stream_cfg['udp_src_port']:
@@ -205,6 +204,8 @@ class TRex(AbstractTrafficGenerator):
         idx_lat = None
         streams = []
         if l2frame == 'IMIX':
+            min_size = 64 if stream_cfg['vlan_tag'] is None else 68
+            self.adjust_imix_min_size(min_size)
             for t, (ratio, l2_frame_size) in enumerate(zip(self.imix_ratios, self.imix_l2_sizes)):
                 pkt = self.create_pkt(stream_cfg, l2_frame_size)
                 streams.append(STLStream(packet=pkt,