[PATCH net-next v4 2/4] selftests: drv-net: add an iperf performance test

[Stanislav Fomichev <sdf.kernel@gmail.com>]

Add the drivers/net/perf target, with a lib/py of its own like the one of
drivers/net/hw. Add Iperf3Runner.measure(), which returns an Iperf3Result
that other results can join later, and report its throughput from the test.

Single-stream iperf3 throughput is flaky and can change considerably
between back-to-back runs on the same hosts.

Tested on two mlx5 hosts. Captured metric output:

  # # ktap-metric-json: {"goal":"higher","name":"throughput","value":49.92071602072054}

Reviewed-by: Björn Töpel <bjorn@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
 tools/testing/selftests/Makefile              |  2 +-
 .../selftests/drivers/net/lib/py/load.py      | 20 ++++++-
 .../selftests/drivers/net/perf/Makefile       | 11 ++++
 .../testing/selftests/drivers/net/perf/config |  1 +
 .../selftests/drivers/net/perf/iperf.py       | 23 ++++++++
 .../drivers/net/perf/lib/py/__init__.py       | 57 +++++++++++++++++++
 .../selftests/drivers/net/perf/settings       |  1 +
 7 files changed, 111 insertions(+), 4 deletions(-)
 create mode 100644 tools/testing/selftests/drivers/net/perf/Makefile
 create mode 100644 tools/testing/selftests/drivers/net/perf/config
 create mode 100755 tools/testing/selftests/drivers/net/perf/iperf.py
 create mode 100644 tools/testing/selftests/drivers/net/perf/lib/py/__init__.py
 create mode 100644 tools/testing/selftests/drivers/net/perf/settings

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 07c3719f8b04..c55d7792b27c 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -159,7 +159,7 @@ 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 ($(filter net drivers/net drivers/net/hw drivers/net/perf,$(TARGETS)),)
 ifeq ($(filter net/lib,$(TARGETS)),)
 	INSTALL_DEP_TARGETS := net/lib
 endif
diff --git a/tools/testing/selftests/drivers/net/lib/py/load.py b/tools/testing/selftests/drivers/net/lib/py/load.py
index e24660e5c27f..f337b576c4b4 100644
--- a/tools/testing/selftests/drivers/net/lib/py/load.py
+++ b/tools/testing/selftests/drivers/net/lib/py/load.py
@@ -3,10 +3,18 @@
 import re
 import time
 import json
+from dataclasses import dataclass
 
 from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
 
 
+@dataclass
+class Iperf3Result:
+    """Average throughput (Gbps) of an iperf3 run."""
+
+    throughput: float
+
+
 class Iperf3Runner:
     """
     Sets up and runs iperf3 traffic.
@@ -53,9 +61,9 @@ 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(self, reverse=False):
         """
-        Runs an iperf3 measurement and returns the average bandwidth (Gbps).
+        Runs an iperf3 measurement and returns an Iperf3Result.
         Discards the first and last few reporting intervals and uses only the
         middle part of the run where throughput is typically stable.
         """
@@ -78,7 +86,13 @@ from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
 
         avg = sum(stable) / len(stable)
 
-        return avg
+        return Iperf3Result(avg)
+
+    def measure_bandwidth(self, reverse=False):
+        """
+        Runs an iperf3 measurement and returns the average bandwidth (Gbps).
+        """
+        return self.measure(reverse=reverse).throughput
 
 
 class GenerateTraffic:
diff --git a/tools/testing/selftests/drivers/net/perf/Makefile b/tools/testing/selftests/drivers/net/perf/Makefile
new file mode 100644
index 000000000000..31b0b60de4f6
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/perf/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS := \
+	iperf.py \
+# end of TEST_PROGS
+
+TEST_INCLUDES := \
+	$(wildcard lib/py/*.py ../lib/py/*.py) \
+# end of TEST_INCLUDES
+
+include ../../../lib.mk
diff --git a/tools/testing/selftests/drivers/net/perf/config b/tools/testing/selftests/drivers/net/perf/config
new file mode 100644
index 000000000000..6450f34933e6
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/perf/config
@@ -0,0 +1 @@
+CONFIG_IPV6=y
diff --git a/tools/testing/selftests/drivers/net/perf/iperf.py b/tools/testing/selftests/drivers/net/perf/iperf.py
new file mode 100755
index 000000000000..5b6f0bce2a03
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/perf/iperf.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""Measure TCP throughput with iperf3."""
+
+from lib.py import Iperf3Runner, NetDrvEpEnv, ksft_exit, ksft_metric, ksft_run
+
+
+def tcp(cfg):
+    """Measure TCP throughput."""
+    result = Iperf3Runner(cfg).measure()
+    ksft_metric("throughput", result.throughput, goal="higher")
+
+
+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()
diff --git a/tools/testing/selftests/drivers/net/perf/lib/py/__init__.py b/tools/testing/selftests/drivers/net/perf/lib/py/__init__.py
new file mode 100644
index 000000000000..f16606cedd00
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/perf/lib/py/__init__.py
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Driver test environment (performance tests).
+NetDrvEnv and NetDrvEpEnv are the main environment classes.
+NetDrvContEnv extends NetDrvEpEnv with netkit container support.
+Former is for local host only tests, latter creates / connects
+to a remote endpoint. See NIPA wiki for more information about
+running and writing driver tests.
+"""
+
+import sys
+from pathlib import Path
+
+KSFT_DIR = (Path(__file__).parent / "../../../../..").resolve()
+
+try:
+    sys.path.append(KSFT_DIR.as_posix())
+
+    # Import one by one to avoid pylint false positives
+    from net.lib.py import NetNS, NetNSEnter, NetdevSimDev, UserNetNS
+    from net.lib.py import EthtoolFamily, NetdevFamily, NetshaperFamily, \
+        NlError, RtnlFamily, DevlinkFamily, PSPFamily, Netlink
+    from net.lib.py import CmdExitFailure
+    from net.lib.py import bkg, cmd, bpftool, bpftrace, defer, ethtool, \
+        fd_read_timeout, ip, rand_port, rand_ports, wait_port_listen, \
+        wait_file, ctl_file_write, tool
+    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_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
+    from drivers.net.lib.py import set_ethtool_feat
+    from drivers.net.lib.py import GenerateTraffic, Remote, Iperf3Runner
+    from drivers.net.lib.py import NetDrvEnv, NetDrvEpEnv, NetDrvContEnv
+
+    __all__ = ["NetNS", "NetNSEnter", "NetdevSimDev", "UserNetNS",
+               "EthtoolFamily", "NetdevFamily", "NetshaperFamily",
+               "NlError", "RtnlFamily", "DevlinkFamily", "PSPFamily", "Netlink",
+               "CmdExitFailure",
+               "bkg", "cmd", "bpftool", "bpftrace", "defer", "ethtool",
+               "fd_read_timeout", "ip", "rand_port", "rand_ports",
+               "wait_port_listen", "wait_file", "ctl_file_write", "tool",
+               "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
+               "KsftSkipEx", "KsftFailEx", "KsftXfailEx",
+               "ksft_disruptive", "ksft_exit", "ksft_metric", "ksft_pr",
+               "ksft_run", "ksft_setup", "ksft_variants", "KsftNamedVariant",
+               "ksft_eq", "ksft_ge", "ksft_in", "ksft_is", "ksft_lt",
+               "ksft_ne", "ksft_not_in", "ksft_raises", "ksft_true", "ksft_gt",
+               "ksft_not_none",
+               "NetDrvEnv", "NetDrvEpEnv", "NetDrvContEnv", "GenerateTraffic",
+               "Remote", "Iperf3Runner", "set_ethtool_feat"]
+except ModuleNotFoundError as e:
+    print("Failed importing `net` library from kernel sources")
+    print(str(e))
+    sys.exit(4)  # KSFT_SKIP
diff --git a/tools/testing/selftests/drivers/net/perf/settings b/tools/testing/selftests/drivers/net/perf/settings
new file mode 100644
index 000000000000..e7b9417537fb
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/perf/settings
@@ -0,0 +1 @@
+timeout=0
-- 
2.53.0-Meta