[RFC net-next 4/6] selftests: drv-net: add an iperf performance test

@@ -32,6 +32,7 @@ TEST_PROGS = \
 	hw_stats_l3.sh \
 	hw_stats_l3_gre.sh \
 	iou-zcrx.py \
+	iperf.py \
 	ipsec_vxlan.py \
 	irq.py \
 	loopback.sh \

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+from lib.py import (Iperf3Runner, NetDrvEpEnv, SystemMonitor, ksft_exit,
+                    ksft_run)
+
+
+def test_iperf(cfg):
+    """Measure TCP throughput while sampling system utilization."""
+    with SystemMonitor(cfg):
+        Iperf3Runner(cfg).measure_bandwidth()
+
+
+def main():
+    with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
+        ksft_run([test_iperf], args=(cfg,))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()

@@ -28,8 +28,8 @@ KSFT_DIR = (Path(__file__).parent / "../../../../..").resolve()
     from net.lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
     from net.lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx
     from net.lib.py import ksft_disruptive, ksft_exit, ksft_metric, \
-        ksft_metric_aggregate, ksft_metric_reporting, ksft_pr, ksft_run, \
-        ksft_setup, \
+        ksft_metric_aggregate, ksft_metric_reporting, \
+        ksft_metric_reporting_enabled, ksft_pr, ksft_run, ksft_setup, \
         ksft_variants, KsftNamedVariant
     from net.lib.py import ksft_eq, ksft_ge, ksft_in, ksft_is, ksft_lt, \
         ksft_ne, ksft_not_in, ksft_raises, ksft_true, ksft_gt, ksft_not_none

@@ -47,8 +47,8 @@ KSFT_DIR = (Path(__file__).parent / "../../../../..").resolve()
                "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
                "KsftSkipEx", "KsftFailEx", "KsftXfailEx",
                "ksft_disruptive", "ksft_exit", "ksft_metric",
-               "ksft_metric_aggregate", "ksft_metric_reporting", "ksft_pr",
-               "ksft_run",
+               "ksft_metric_aggregate", "ksft_metric_reporting",
+               "ksft_metric_reporting_enabled", "ksft_pr", "ksft_run",
                "ksft_setup", "ksft_variants",
                "KsftNamedVariant",
                "ksft_eq", "ksft_ge", "ksft_in", "ksft_is", "ksft_lt",

@@ -28,8 +28,8 @@ KSFT_DIR = (Path(__file__).parent / "../../../..").resolve()
     from net.lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
     from net.lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx
     from net.lib.py import ksft_disruptive, ksft_exit, ksft_metric, \
-        ksft_metric_aggregate, ksft_metric_reporting, ksft_pr, ksft_run, \
-        ksft_setup, \
+        ksft_metric_aggregate, ksft_metric_reporting, \
+        ksft_metric_reporting_enabled, ksft_pr, ksft_run, ksft_setup, \
         ksft_variants, KsftNamedVariant
     from net.lib.py import ksft_eq, ksft_ge, ksft_in, ksft_is, ksft_lt, \
         ksft_ne, ksft_not_in, ksft_raises, ksft_true, ksft_gt, ksft_not_none

@@ -44,8 +44,8 @@ KSFT_DIR = (Path(__file__).parent / "../../../..").resolve()
                "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
                "KsftSkipEx", "KsftFailEx", "KsftXfailEx",
                "ksft_disruptive", "ksft_exit", "ksft_metric",
-               "ksft_metric_aggregate", "ksft_metric_reporting", "ksft_pr",
-               "ksft_run",
+               "ksft_metric_aggregate", "ksft_metric_reporting",
+               "ksft_metric_reporting_enabled", "ksft_pr", "ksft_run",
                "ksft_setup", "ksft_variants",
                "KsftNamedVariant",
                "ksft_eq", "ksft_ge", "ksft_in", "ksft_is", "ksft_lt",

@@ -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_aggregate, \
+    ksft_metric_reporting_enabled, ksft_pr, rand_port, wait_port_listen
 
 
 class Iperf3Runner:

@@ -57,8 +58,17 @@ from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
         """
         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.
+        middle part of the run where throughput is typically stable. When a
+        SystemMonitor is active, also emit throughput and retransmit metrics.
         """
+        report_metrics = ksft_metric_reporting_enabled()
+        if report_metrics:
+            ksft_metric_aggregate(
+                "throughput", summarize="distribution",
+                regression={"compare": "p50", "better": "higher",
+                            "relative_tolerance": 0.05})
+            ksft_metric_aggregate("tcp.retransmits", summarize="max")
+
         self.start_server()
         result = self.start_client(duration=10, reverse=reverse)
 

@@ -77,6 +87,17 @@ 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_metrics:
+            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, shape="scalar", host=receiver)
+            ksft_metric("tcp.retransmits", retransmits, shape="scalar",
+                        host=sender)
 
         return avg
 

@@ -9,7 +9,7 @@ from .ksft import KsftFailEx, KsftSkipEx, KsftXfailEx, ksft_pr, ksft_eq, \
     ksft_ne, ksft_true, ksft_not_none, ksft_in, ksft_not_in, ksft_is, \
     ksft_ge, ksft_gt, ksft_lt, ksft_raises, ksft_busy_wait, \
     ktap_result, ksft_disruptive, ksft_metric, ksft_metric_aggregate, \
-    ksft_metric_reporting, ksft_setup, ksft_run, \
+    ksft_metric_reporting, ksft_metric_reporting_enabled, ksft_setup, ksft_run, \
     ksft_exit, ksft_variants, KsftNamedVariant
 from .netns import NetNS, NetNSEnter, UserNetNS
 from .nsim import NetdevSim, NetdevSimDev

@@ -26,8 +26,8 @@ __all__ = ["KSRC",
            "ksft_ne", "ksft_true", "ksft_not_none", "ksft_in", "ksft_not_in",
            "ksft_is", "ksft_ge", "ksft_gt", "ksft_lt", "ksft_raises",
            "ksft_busy_wait", "ktap_result", "ksft_disruptive", "ksft_metric",
-           "ksft_metric_aggregate", "ksft_metric_reporting", "ksft_setup",
-           "ksft_run",
+           "ksft_metric_aggregate", "ksft_metric_reporting",
+           "ksft_metric_reporting_enabled", "ksft_setup", "ksft_run",
            "ksft_exit", "ksft_variants",
            "KsftNamedVariant",
            "NetNS", "NetNSEnter", "UserNetNS",

@@ -108,6 +108,12 @@ KSFT_METRICS_LOCK = threading.Lock()
         KSFT_METRIC_REPORTING += 1 if enable else -1
 
 
+def ksft_metric_reporting_enabled():
+    """Return whether benchmark metric producers should emit metrics."""
+    with KSFT_METRICS_LOCK:
+        return KSFT_METRIC_REPORTING > 0
+
+
 def ksft_metric_aggregate(name, summarize="total", *, aggregation=None,
                           transform=None, regression=None,
                           display_range=None, display_scale=None,