dpdk: testpmd check packet drops

Gathers and checks packet drops at the end of send receive tests. Senders are allowed to drop more packets, we intentionally tune it to maximize the PPS, so some drops are expected. The rough metric in this PR is that the percentage of packets dropped should not exceed 20% on the sender and 1% on the receiver.

Author: mcgov

lisa/microsoft/testsuites/dpdk/dpdktestpmd.py

@@ -411,10 +411,18 @@ def command(self) -> str:
 
     _tx_pps_key = "transmit-packets-per-second"
     _rx_pps_key = "receive-packets-per-second"
+    _tx_drop_key = "tx-packet-drops"
+    _rx_drop_key = "rx-packet-drops"
+    _tx_total_key = "tx-total-packets"
+    _rx_total_key = "rx-total-packets"
 
     _testpmd_output_regex = {
         _tx_pps_key: r"Tx-pps:\s+([0-9]+)",
         _rx_pps_key: r"Rx-pps:\s+([0-9]+)",
+        _tx_drop_key: r"TX-dropped:\s+([0-9]+)",
+        _rx_drop_key: r"RX-dropped:\s+([0-9]+)",
+        _tx_total_key: r"TX-packets:\s+([0-9]+)",
+        _rx_total_key: r"TX-packets:\s+([0-9]+)",
     }
     _source_build_dest_dir = "/usr/local/bin"
 
@@ -716,6 +724,18 @@ def populate_performance_data(self) -> None:
         self.tx_pps_data = self.get_data_from_testpmd_output(
             self._tx_pps_key, self._last_run_output
         )
+        self.tx_packet_drops = self.get_data_from_testpmd_output(
+            self._tx_drop_key, self._last_run_output
+        )[-1]
+        self.rx_packet_drops = self.get_data_from_testpmd_output(
+            self._rx_drop_key, self._last_run_output
+        )[-1]
+        self.tx_total_packets = self.get_data_from_testpmd_output(
+            self._tx_total_key, self._last_run_output
+        )[-1]
+        self.rx_total_packets = self.get_data_from_testpmd_output(
+            self._rx_total_key, self._last_run_output
+        )[-1]
 
     def get_mean_rx_pps(self) -> int:
         self._check_pps_data("RX")
@@ -741,6 +761,26 @@ def get_min_tx_pps(self) -> int:
         self._check_pps_data("TX")
         return min(self.tx_pps_data)
 
+    def check_tx_packet_drops(self) -> None:
+        if self.tx_total_packets == 0:
+            raise AssertionError(
+                "Test bug: tx packet data was 0, could not check dropped packets"
+            )
+        dropped_packet_percentage = self.tx_packet_drops / self.tx_total_packets
+        assert_that(dropped_packet_percentage).described_as(
+            "More than 20% of the tx packets were dropped!"
+        ).is_close_to(0, 0.2)
+
+    def check_rx_packet_drops(self) -> None:
+        if self.rx_total_packets == 0:
+            raise AssertionError(
+                "Test bug: rx packet data was 0 could not check dropped packets."
+            )
+        dropped_packet_percentage = self.rx_packet_drops / self.rx_total_packets
+        assert_that(dropped_packet_percentage).described_as(
+            "More than 1% of the received packets were dropped!"
+        ).is_close_to(0, 0.01)
+
     def get_mean_tx_pps_sriov_hotplug(self) -> Tuple[int, int, int]:
         return self._get_pps_sriov_hotplug(self._tx_pps_key)
 

lisa/microsoft/testsuites/dpdk/dpdkutil.py

@@ -672,6 +672,12 @@ def verify_dpdk_send_receive(
         "Throughput for SEND was below the correct order of magnitude"
     ).is_greater_than(2**20)
 
+    # verify sender didn't drop most of the packets
+    sender.testpmd.check_tx_packet_drops()
+
+    # verify receiver didn't drop most of the packets
+    receiver.testpmd.check_rx_packet_drops()
+
     return sender, receiver