[RFC net-next v2 3/5] selftests: drv-net: add an iperf performance test

@@ -152,7 +152,7 @@ TARGETS_HOTPLUG = cpu-hotplug
 TARGETS_HOTPLUG += memory-hotplug
 
 # Networking tests want the net/lib target, include it automatically
-ifneq ($(filter net drivers/net drivers/net/hw,$(TARGETS)),)
+ifneq ($(filter net drivers/net drivers/net/hw drivers/net/hw/performance,$(TARGETS)),)
 ifeq ($(filter net/lib,$(TARGETS)),)
 	INSTALL_DEP_TARGETS := net/lib
 endif

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS := iperf.py
+
+TEST_INCLUDES := \
+	$(wildcard ../lib/py/*.py ../../lib/py/*.py) \
+	$(wildcard ../../../../net/lib/py/*.py) \
+	#
+
+include ../../../../lib.mk

@@ -0,0 +1 @@
+CONFIG_IPV6=y

@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""Measure TCP throughput with iperf3."""
+
+from os import path
+import sys
+
+sys.path.insert(0, path.join(path.dirname(path.abspath(__file__)), ".."))
+
+from lib.py import Iperf3Runner, NetDrvEpEnv, ksft_exit, ksft_run
+
+
+def tcp(cfg):
+    """Measure TCP throughput."""
+    Iperf3Runner(cfg).measure_bandwidth(report=True)
+
+
+def main():
+    """Run the iperf performance test."""
+    with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
+        ksft_run([tcp], args=(cfg,))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()

@@ -0,0 +1 @@
+timeout=0

@@ -4,7 +4,8 @@ import re
 import time
 import json
 
-from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
+from lib.py import cmd, ip, ksft_metric, ksft_metric_policy, ksft_pr, \
+    rand_port, wait_port_listen
 
 
 class Iperf3Runner:

@@ -53,12 +54,20 @@ from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
             kwargs["timeout"] = duration + 5
         return cmd(cmdline, **kwargs)
 
-    def measure_bandwidth(self, reverse=False):
+    def measure_bandwidth(self, reverse=False, report=False):
         """
         Runs an iperf3 measurement and returns the average bandwidth (Gbps).
         Discards the first and last few reporting intervals and uses only the
         middle part of the run where throughput is typically stable.
         """
+        if report:
+            ksft_metric_policy(
+                "throughput", summarize="p50",
+                regression={"compare": "p50", "better": "higher",
+                            "relative_tolerance": 0.05},
+                display_label="Gbps")
+            ksft_metric_policy("tcp.retransmits", summarize="max")
+
         self.start_server()
         result = self.start_client(duration=10, reverse=reverse)
 

@@ -77,6 +86,17 @@ from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
         stable = samples[3:-3]
 
         avg = sum(stable) / len(stable)
+        retransmits = out.get("end", {}).get("sum_sent", {}).get(
+            "retransmits")
+        if report:
+            if not isinstance(retransmits, int) or \
+                    isinstance(retransmits, bool):
+                raise ValueError("iperf3 did not report TCP retransmits")
+            receiver = "remote" if reverse else "local"
+            sender = "local" if reverse else "remote"
+            ksft_metric("throughput", avg, kind="scalar", host=receiver)
+            ksft_metric("tcp.retransmits", retransmits, kind="scalar",
+                        host=sender)
 
         return avg