[PATCH net-next 0/6] selftests: drv-net: Fix issues in devlink_rate_tc_bw.py

[PATCH net-next 0/6] selftests: drv-net: Fix issues in devlink_rate_tc_bw.py

[Carolina Jubran]

Hi,

This series fixes issues in the devlink_rate_tc_bw.py selftest and
introduces a new Iperf3Runner that helps with measurement handling.

Thanks,
Carolina

Carolina Jubran (6):
  selftests: drv-net: Add devlink_rate_tc_bw.py to TEST_PROGS
  selftests: drv-net: introduce Iperf3Runner for measurement use cases
  selftests: drv-net: Use Iperf3Runner in devlink_rate_tc_bw.py
  selftests: drv-net: Set shell=True for sysfs writes in
    devlink_rate_tc_bw.py
  selftests: drv-net: Fix and clarify TC bandwidth split in
    devlink_rate_tc_bw.py
  selftests: drv-net: Fix tolerance calculation in devlink_rate_tc_bw.py

 .../testing/selftests/drivers/net/hw/Makefile |   1 +
 .../drivers/net/hw/devlink_rate_tc_bw.py      | 174 ++++++++----------
 .../drivers/net/hw/lib/py/__init__.py         |   5 +-
 .../selftests/drivers/net/lib/py/__init__.py  |   5 +-
 .../selftests/drivers/net/lib/py/load.py      |  84 ++++++++-
 5 files changed, 157 insertions(+), 112 deletions(-)

-- 
2.38.1

[PATCH net-next 1/6] selftests: drv-net: Add devlink_rate_tc_bw.py to TEST_PROGS

[Carolina Jubran]

This makes devlink_rate_tc_bw.py present in the Makefile under the same
directory.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
---
 tools/testing/selftests/drivers/net/hw/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index 8133d1a0051c..2f53eaa929b7 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -23,6 +23,7 @@ TEST_PROGS = \
 	rss_input_xfrm.py \
 	tso.py \
 	xsk_reconfig.py \
+	devlink_rate_tc_bw.py \
 	#
 
 TEST_FILES := \
-- 
2.38.1

Re: [PATCH net-next 1/6] selftests: drv-net: Add devlink_rate_tc_bw.py to TEST_PROGS

[Jakub Kicinski]

On Thu, 20 Nov 2025 11:58:54 +0200 Carolina Jubran wrote:
> diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
> index 8133d1a0051c..2f53eaa929b7 100644
> --- a/tools/testing/selftests/drivers/net/hw/Makefile
> +++ b/tools/testing/selftests/drivers/net/hw/Makefile
> @@ -23,6 +23,7 @@ TEST_PROGS = \
>  	rss_input_xfrm.py \
>  	tso.py \
>  	xsk_reconfig.py \
> +	devlink_rate_tc_bw.py \
>  	#

These need to be added in the right spot, we wanted them sorted.
Otherwise everyone tries to add at the end and there's a lot of
easily avoidable conflicts.

[PATCH net-next 2/6] selftests: drv-net: introduce Iperf3Runner for measurement use cases

[Carolina Jubran]

GenerateTraffic was added to spin up long-running iperf3 load, mainly
to drive high PPS background traffic. It was never meant to provide
stable throughput numbers, and trying to repurpose it for measurement
does not make sense.

Introduce Iperf3Runner to allow tests to split out server/client
configuration, control start/stop, and collect JSON output for
analysis. This makes it possible to measure bandwidth directly when
validating egress shaping.

GenerateTraffic stays as the background load generator, reusing the
common iperf3 helpers under the hood.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
---
 .../drivers/net/hw/lib/py/__init__.py         |  5 +-
 .../selftests/drivers/net/lib/py/__init__.py  |  5 +-
 .../selftests/drivers/net/lib/py/load.py      | 84 +++++++++++++++++--
 3 files changed, 82 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
index fb010a48a5a1..7563a49fca65 100644
--- a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
@@ -28,7 +28,7 @@ try:
         ksft_setup
     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 GenerateTraffic, Remote
+    from drivers.net.lib.py import GenerateTraffic, Remote, Iperf3Runner
     from drivers.net.lib.py import NetDrvEnv, NetDrvEpEnv
 
     __all__ = ["NetNS", "NetNSEnter", "NetdevSimDev",
@@ -44,7 +44,8 @@ try:
                "ksft_eq", "ksft_ge", "ksft_in", "ksft_is", "ksft_lt",
                "ksft_ne", "ksft_not_in", "ksft_raises", "ksft_true", "ksft_gt",
                "ksft_not_none", "ksft_not_none",
-               "NetDrvEnv", "NetDrvEpEnv", "GenerateTraffic", "Remote"]
+               "NetDrvEnv", "NetDrvEpEnv", "GenerateTraffic", "Remote",
+               "Iperf3Runner"]
 except ModuleNotFoundError as e:
     print("Failed importing `net` library from kernel sources")
     print(str(e))
diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py
index b0c6300150fb..65de853e8ac6 100644
--- a/tools/testing/selftests/drivers/net/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py
@@ -44,10 +44,11 @@ try:
                "ksft_not_none", "ksft_not_none"]
 
     from .env import NetDrvEnv, NetDrvEpEnv
-    from .load import GenerateTraffic
+    from .load import GenerateTraffic, Iperf3Runner
     from .remote import Remote
 
-    __all__ += ["NetDrvEnv", "NetDrvEpEnv", "GenerateTraffic", "Remote"]
+    __all__ += ["NetDrvEnv", "NetDrvEpEnv", "GenerateTraffic", "Remote",
+                "Iperf3Runner"]
 except ModuleNotFoundError as e:
     print("Failed importing `net` library from kernel sources")
     print(str(e))
diff --git a/tools/testing/selftests/drivers/net/lib/py/load.py b/tools/testing/selftests/drivers/net/lib/py/load.py
index c4e808407cc4..cef661ded8ab 100644
--- a/tools/testing/selftests/drivers/net/lib/py/load.py
+++ b/tools/testing/selftests/drivers/net/lib/py/load.py
@@ -2,21 +2,89 @@
 
 import re
 import time
+import json
 
 from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
 
-class GenerateTraffic:
-    def __init__(self, env, port=None):
-        env.require_cmd("iperf3", local=True, remote=True)
 
+class Iperf3Runner:
+    """
+    Sets up and runs iperf3 traffic.
+    """
+    def __init__(self, env, port=None, server_ip=None, client_ip=None):
+        env.require_cmd("iperf3", local=True, remote=True)
         self.env = env
-
         self.port = rand_port() if port is None else port
-        self._iperf_server = cmd(f"iperf3 -s -1 -p {self.port}", background=True)
+        self.server_ip = server_ip
+        self.client_ip = client_ip
+
+    def _build_server(self):
+        cmdline = f"iperf3 -s -1 -p {self.port}"
+        if self.server_ip:
+            cmdline += f" -B {self.server_ip}"
+        return cmdline
+
+    def _build_client(self, streams, duration, reverse):
+        host = self.env.addr if self.server_ip is None else self.server_ip
+        cmdline = f"iperf3 -c {host} -p {self.port} -P {streams} -t {duration} -J"
+        if self.client_ip:
+            cmdline += f" -B {self.client_ip}"
+        if reverse:
+            cmdline += " --reverse"
+        return cmdline
+
+    def start_server(self):
+        """
+        Starts an iperf3 server with optional bind IP.
+        """
+        cmdline = self._build_server()
+        proc = cmd(cmdline, background=True)
         wait_port_listen(self.port)
         time.sleep(0.1)
-        self._iperf_client = cmd(f"iperf3 -c {env.addr} -P 16 -p {self.port} -t 86400",
-                                 background=True, host=env.remote)
+        return proc
+
+    def start_client(self, background=False, streams=1, duration=10, reverse=False):
+        """
+        Starts the iperf3 client with the configured options.
+        """
+        cmdline = self._build_client(streams, duration, reverse)
+        return cmd(cmdline, background=background, host=self.env.remote)
+
+    def measure_bandwidth(self, reverse=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.
+        """
+        self.start_server()
+        result = self.start_client(duration=10, reverse=reverse)
+
+        if result.ret != 0:
+            raise Exception("iperf3 failed to run successfully")
+        try:
+            out = json.loads(result.stdout)
+        except json.JSONDecodeError as exc:
+            raise Exception("Failed to parse iperf3 JSON output") from exc
+
+        intervals = out.get("intervals", [])
+        samples = [i["sum"]["bits_per_second"] / 1e9 for i in intervals]
+        if len(samples) < 10:
+            raise Exception(f"iperf3 returned too few intervals: {len(samples)}")
+        # Discard potentially unstable first and last 3 seconds.
+        stable = samples[3:-3]
+
+        avg = sum(stable) / len(stable)
+
+        return avg
+
+
+class GenerateTraffic:
+    def __init__(self, env, port=None):
+        self.env = env
+        self.runner = Iperf3Runner(env, port)
+
+        self._iperf_server = self.runner.start_server()
+        self._iperf_client = self.runner.start_client(background=True, streams=16, duration=86400)
 
         # Wait for traffic to ramp up
         if not self._wait_pkts(pps=1000):
@@ -61,7 +129,7 @@ class GenerateTraffic:
     def _wait_client_stopped(self, sleep=0.005, timeout=5):
         end = time.monotonic() + timeout
 
-        live_port_pattern = re.compile(fr":{self.port:04X} 0[^6] ")
+        live_port_pattern = re.compile(fr":{self.runner.port:04X} 0[^6] ")
 
         while time.monotonic() < end:
             data = cmd("cat /proc/net/tcp*", host=self.env.remote).stdout
-- 
2.38.1

[PATCH net-next 3/6] selftests: drv-net: Use Iperf3Runner in devlink_rate_tc_bw.py

[Carolina Jubran]

Replace the inline iperf3 subprocess and JSON parsing with
Iperf3Runner.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
---
 .../drivers/net/hw/devlink_rate_tc_bw.py      | 70 ++++++++-----------
 1 file changed, 29 insertions(+), 41 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
index ead6784d1910..16e5dda5bee1 100755
--- a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
+++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
@@ -64,6 +64,7 @@ from lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx
 from lib.py import NetDrvEpEnv, DevlinkFamily
 from lib.py import NlError
 from lib.py import cmd, defer, ethtool, ip
+from lib.py import Iperf3Runner
 
 
 class BandwidthValidator:
@@ -139,8 +140,8 @@ def setup_vlans_on_vf(vf_ifc):
     Sets up two VLAN interfaces on the given VF, each mapped to a different TC.
     """
     vlan_configs = [
-        {"vlan_id": 101, "tc": 3, "ip": "198.51.100.2"},
-        {"vlan_id": 102, "tc": 4, "ip": "198.51.100.10"},
+        {"vlan_id": 101, "tc": 3, "ip": "198.51.100.1"},
+        {"vlan_id": 102, "tc": 4, "ip": "198.51.100.9"},
     ]
 
     for config in vlan_configs:
@@ -224,13 +225,13 @@ def setup_devlink_rate(cfg):
         raise KsftFailEx(f"rate_set failed on VF port {port_index}") from exc
 
 
-def setup_remote_server(cfg):
+def setup_remote_vlans(cfg):
     """
-    Sets up VLAN interfaces and starts iperf3 servers on the remote side.
+    Sets up VLAN interfaces on the remote side.
     """
     remote_dev = cfg.remote_ifname
     vlan_ids = [101, 102]
-    remote_ips = ["198.51.100.1", "198.51.100.9"]
+    remote_ips = ["198.51.100.2", "198.51.100.10"]
 
     for vlan_id, ip_addr in zip(vlan_ids, remote_ips):
         vlan_dev = f"{remote_dev}.{vlan_id}"
@@ -238,14 +239,13 @@ def setup_remote_server(cfg):
             f"type vlan id {vlan_id}", host=cfg.remote)
         cmd(f"ip addr add {ip_addr}/29 dev {vlan_dev}", host=cfg.remote)
         cmd(f"ip link set dev {vlan_dev} up", host=cfg.remote)
-        cmd(f"iperf3 -s -1 -B {ip_addr}",background=True, host=cfg.remote)
         defer(cmd, f"ip link del {vlan_dev}", host=cfg.remote)
 
 
 def setup_test_environment(cfg, set_tc_mapping=True):
     """
     Sets up the complete test environment including VF creation, VLANs,
-    bridge configuration, devlink rate setup, and the remote server.
+    bridge configuration and devlink rate setup.
     """
     vf_ifc = setup_vf(cfg, set_tc_mapping)
     ksft_pr(f"Created VF interface: {vf_ifc}")
@@ -256,51 +256,39 @@ def setup_test_environment(cfg, set_tc_mapping=True):
     setup_bridge(cfg)
 
     setup_devlink_rate(cfg)
-    setup_remote_server(cfg)
-    time.sleep(2)
+    setup_remote_vlans(cfg)
 
 
-def run_iperf_client(server_ip, local_ip, barrier, min_expected_gbps=0.1):
+def measure_bandwidth(cfg, server_ip, client_ip, barrier):
     """
-    Runs a single iperf3 client instance, binding to the given local IP.
-    Waits on a barrier to synchronize with other threads.
+    Synchronizes with peers and runs an iperf3-based bandwidth measurement
+    between the given endpoints. Returns average Gbps.
     """
+    runner = Iperf3Runner(cfg, server_ip=server_ip, client_ip=client_ip)
     try:
         barrier.wait(timeout=10)
     except Exception as exc:
         raise KsftFailEx("iperf3 barrier wait timed") from exc
 
-    iperf_cmd = ["iperf3", "-c", server_ip, "-B", local_ip, "-J"]
-    result = subprocess.run(iperf_cmd, capture_output=True, text=True,
-                            check=True)
-
     try:
-        output = json.loads(result.stdout)
-        bits_per_second = output["end"]["sum_received"]["bits_per_second"]
-        gbps = bits_per_second / 1e9
-        if gbps < min_expected_gbps:
-            ksft_pr(
-                f"iperf3 bandwidth too low: {gbps:.2f} Gbps "
-                f"(expected ≥ {min_expected_gbps} Gbps)"
-            )
-            return None
-        return gbps
-    except json.JSONDecodeError as exc:
-        ksft_pr(f"Failed to parse iperf3 JSON output: {exc}")
-        return None
+        bw_gbps = runner.measure_bandwidth(reverse=True)
+    except Exception as exc:
+        raise KsftFailEx("iperf3 bandwidth measurement failed") from exc
 
+    return bw_gbps
 
-def run_bandwidth_test():
+
+def run_bandwidth_test(cfg):
     """
-    Launches iperf3 client threads for each VLAN/TC pair and collects results.
+    Runs parallel bandwidth measurements for each VLAN/TC pair and collects results.
     """
-    def _run_iperf_client_thread(server_ip, local_ip, results, barrier, tc_ix):
-        results[tc_ix] = run_iperf_client(server_ip, local_ip, barrier)
+    def _run_measure_bandwidth_thread(local_ip, remote_ip, results, barrier, tc_ix):
+        results[tc_ix] = measure_bandwidth(cfg, local_ip, remote_ip, barrier)
 
     vf_vlan_data = [
         # (local_ip, remote_ip, TC)
-        ("198.51.100.2",  "198.51.100.1", 3),
-        ("198.51.100.10", "198.51.100.9", 4),
+        ("198.51.100.1",  "198.51.100.2", 3),
+        ("198.51.100.9", "198.51.100.10", 4),
     ]
 
     results = {}
@@ -309,8 +297,8 @@ def run_bandwidth_test():
 
     for local_ip, remote_ip, tc_ix in vf_vlan_data:
         thread = threading.Thread(
-            target=_run_iperf_client_thread,
-            args=(remote_ip, local_ip, results, start_barrier, tc_ix)
+            target=_run_measure_bandwidth_thread,
+            args=(local_ip, remote_ip, results, start_barrier, tc_ix)
         )
         thread.start()
         threads.append(thread)
@@ -320,10 +308,11 @@ def run_bandwidth_test():
 
     for tc_ix, tc_bw in results.items():
         if tc_bw is None:
-            raise KsftFailEx("iperf3 client failed; cannot evaluate bandwidth")
+            raise KsftFailEx("iperf3 failed; cannot evaluate bandwidth")
 
     return results
 
+
 def calculate_bandwidth_percentages(results):
     """
     Calculates the percentage of total bandwidth received by TC3 and TC4.
@@ -398,10 +387,10 @@ def check_bandwidth_distribution(bw_data, validator):
 
 def run_bandwidth_distribution_test(cfg, set_tc_mapping):
     """
-    Runs parallel iperf3 tests for both TCs and collects results.
+    Runs parallel bandwidth measurements for both TCs and collects results.
     """
     setup_test_environment(cfg, set_tc_mapping)
-    bandwidths = run_bandwidth_test()
+    bandwidths = run_bandwidth_test(cfg)
     bw_data = calculate_bandwidth_percentages(bandwidths)
     test_name = "with TC mapping" if set_tc_mapping else "without TC mapping"
     print_bandwidth_results(bw_data, test_name)
@@ -451,7 +440,6 @@ def main() -> None:
         )
         if not cfg.pci:
             raise KsftSkipEx("Could not get PCI address of the interface")
-        cfg.require_cmd("iperf3", local=True, remote=True)
 
         cfg.bw_validator = BandwidthValidator()
 
-- 
2.38.1

[PATCH net-next 4/6] selftests: drv-net: Set shell=True for sysfs writes in devlink_rate_tc_bw.py

[Carolina Jubran]

Commit 7c32f7a2d3db ("selftests: net: py: don't default to shell=True")
changed the cmd() helper to avoid spawning a shell unless explicitly
requested.

The devlink_rate_tc_bw test enables SR-IOV by writing to the
sriov_numvfs sysfs attribute using redirection. Without shell=True the
redirection is not interpreted and the VF device never appears,
causing the test to fail.

Fix by explicitly passing shell=True in the two places that update
sriov_numvfs.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
---
 tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
index 16e5dda5bee1..df71936531cf 100755
--- a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
+++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
@@ -117,8 +117,8 @@ def setup_vf(cfg, set_tc_mapping=True):
     except Exception as exc:
         raise KsftSkipEx(f"Failed to enable switchdev mode on {cfg.pci}") from exc
     try:
-        cmd(f"echo 1 > /sys/class/net/{cfg.ifname}/device/sriov_numvfs")
-        defer(cmd, f"echo 0 > /sys/class/net/{cfg.ifname}/device/sriov_numvfs")
+        cmd(f"echo 1 > /sys/class/net/{cfg.ifname}/device/sriov_numvfs", shell=True)
+        defer(cmd, f"echo 0 > /sys/class/net/{cfg.ifname}/device/sriov_numvfs", shell=True)
     except Exception as exc:
         raise KsftSkipEx(f"Failed to enable SR-IOV on {cfg.ifname}") from exc
 
-- 
2.38.1

[PATCH net-next 5/6] selftests: drv-net: Fix and clarify TC bandwidth split in devlink_rate_tc_bw.py

[Carolina Jubran]

Correct the documented bandwidth distribution between TC3 and TC4
from 80/20 to 20/80. Update test descriptions and printed messages
to consistently reflect the intended split.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
---
 .../drivers/net/hw/devlink_rate_tc_bw.py      | 26 +++++++++----------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
index df71936531cf..db24bfc51da4 100755
--- a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
+++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
@@ -21,21 +21,21 @@ Test Cases:
 ----------
 1. test_no_tc_mapping_bandwidth:
    - Verifies that without TC mapping, bandwidth is NOT distributed according to
-     the configured 80/20 split between TC4 and TC3
-   - This test should fail if bandwidth matches the 80/20 split without TC
+     the configured 20/80 split between TC3 and TC4
+   - This test should fail if bandwidth matches the 20/80 split without TC
      mapping
-   - Expected: Bandwidth should NOT be distributed as 80/20
+   - Expected: Bandwidth should NOT be distributed as 20/80
 
 2. test_tc_mapping_bandwidth:
    - Configures TC mapping using mqprio qdisc
    - Verifies that with TC mapping, bandwidth IS distributed according to the
-     configured 80/20 split between TC3 and TC4
-   - Expected: Bandwidth should be distributed as 80/20
+     configured 20/80 split between TC3 and TC4
+   - Expected: Bandwidth should be distributed as 20/80
 
 Bandwidth Distribution:
 ----------------------
-- TC3 (VLAN 101): Configured for 80% of total bandwidth
-- TC4 (VLAN 102): Configured for 20% of total bandwidth
+- TC3 (VLAN 101): Configured for 20% of total bandwidth
+- TC4 (VLAN 102): Configured for 80% of total bandwidth
 - Total bandwidth: 1Gbps
 - Tolerance: +-12%
 
@@ -402,10 +402,10 @@ def run_bandwidth_distribution_test(cfg, set_tc_mapping):
 
 def test_no_tc_mapping_bandwidth(cfg):
     """
-    Verifies that bandwidth is not split 80/20 without traffic class mapping.
+    Verifies that bandwidth is not split 20/80 without traffic class mapping.
     """
-    pass_bw_msg = "Bandwidth is NOT distributed as 80/20 without TC mapping"
-    fail_bw_msg = "Bandwidth matched 80/20 split without TC mapping"
+    pass_bw_msg = "Bandwidth is NOT distributed as 20/80 without TC mapping"
+    fail_bw_msg = "Bandwidth matched 20/80 split without TC mapping"
     is_mlx5 = "driver: mlx5" in ethtool(f"-i {cfg.ifname}").stdout
 
     if run_bandwidth_distribution_test(cfg, set_tc_mapping=False):
@@ -419,13 +419,13 @@ def test_no_tc_mapping_bandwidth(cfg):
 
 def test_tc_mapping_bandwidth(cfg):
     """
-    Verifies that bandwidth is correctly split 80/20 between TC3 and TC4
+    Verifies that bandwidth is correctly split 20/80 between TC3 and TC4
     when traffic class mapping is set.
     """
     if run_bandwidth_distribution_test(cfg, set_tc_mapping=True):
-        ksft_pr("Bandwidth is distributed as 80/20 with TC mapping")
+        ksft_pr("Bandwidth is distributed as 20/80 with TC mapping")
     else:
-        raise KsftFailEx("Bandwidth did not match 80/20 split with TC mapping")
+        raise KsftFailEx("Bandwidth did not match 20/80 split with TC mapping")
 
 
 def main() -> None:
-- 
2.38.1

[PATCH net-next 6/6] selftests: drv-net: Fix tolerance calculation in devlink_rate_tc_bw.py

[Carolina Jubran]

Currently, tolerance is computed against the TC’s expected percentage,
making TC3 (20%) validation overly strict and TC4 (80%) overly loose.

Update BandwidthValidator to take a dict of shares and compute bounds
relative to the overall total, so that all shares are validated
consistently.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
---
 .../drivers/net/hw/devlink_rate_tc_bw.py      | 74 ++++++++-----------
 1 file changed, 30 insertions(+), 44 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
index db24bfc51da4..4e4faa9275bb 100755
--- a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
+++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
@@ -69,39 +69,35 @@ from lib.py import Iperf3Runner
 
 class BandwidthValidator:
     """
-    Validates bandwidth totals and per-TC shares against expected values
-    with a tolerance.
+    Validates total bandwidth and individual shares with tolerance
+    relative to the overall total.
     """
 
-    def __init__(self):
+    def __init__(self, shares):
         self.tolerance_percent = 12
-        self.expected_total_gbps = 1.0
-        self.total_min_expected = self.min_expected(self.expected_total_gbps)
-        self.total_max_expected = self.max_expected(self.expected_total_gbps)
-        self.tc_expected_percent = {
-            3: 20.0,
-            4: 80.0,
-        }
+        self.expected_total = sum(shares.values())
+        self.bounds = {}
+
+        for name, exp in shares.items():
+            self.bounds[name] = (self.min_expected(exp), self.max_expected(exp))
 
     def min_expected(self, value):
         """Calculates the minimum acceptable value based on tolerance."""
-        return value - (value * self.tolerance_percent / 100)
+        return value - (self.expected_total * self.tolerance_percent / 100)
 
     def max_expected(self, value):
         """Calculates the maximum acceptable value based on tolerance."""
-        return value + (value * self.tolerance_percent / 100)
-
-    def bound(self, expected, value):
-        """Returns True if value is within expected tolerance."""
-        return self.min_expected(expected) <= value <= self.max_expected(expected)
+        return value + (self.expected_total * self.tolerance_percent / 100)
 
-    def tc_bandwidth_bound(self, value, tc_ix):
+    def bound(self, values):
         """
-        Returns True if the given bandwidth value is within tolerance
-        for the TC's expected bandwidth.
+        Return True if all given values fall within tolerance.
         """
-        expected = self.tc_expected_percent[tc_ix]
-        return self.bound(expected, value)
+        for name, value in values.items():
+            low, high = self.bounds[name]
+            if not low <= value <= high:
+                return False
+        return True
 
 
 def setup_vf(cfg, set_tc_mapping=True):
@@ -353,38 +349,26 @@ def verify_total_bandwidth(bw_data, validator):
     """
     total = bw_data['total_bw']
 
-    if validator.bound(validator.expected_total_gbps, total):
+    if validator.bound({"total": total}):
         return
 
-    if total < validator.total_min_expected:
+    low, high = validator.bounds["total"]
+
+    if total < low:
         raise KsftSkipEx(
             f"Total bandwidth {total:.2f} Gbps < minimum "
-            f"{validator.total_min_expected:.2f} Gbps; "
-            f"parent tx_max ({validator.expected_total_gbps:.1f} G) "
+            f"{low:.2f} Gbps; "
+            f"parent tx_max ({validator.expected_total:.1f} G) "
             f"not reached, cannot validate share"
         )
 
     raise KsftFailEx(
         f"Total bandwidth {total:.2f} Gbps exceeds allowed ceiling "
-        f"{validator.total_max_expected:.2f} Gbps "
-        f"(VF tx_max set to {validator.expected_total_gbps:.1f} G)"
+        f"{high:.2f} Gbps "
+        f"(VF tx_max set to {validator.expected_total:.1f} G)"
     )
 
 
-def check_bandwidth_distribution(bw_data, validator):
-    """
-    Checks whether the measured TC3 and TC4 bandwidth percentages
-    fall within their expected tolerance ranges.
-
-    Returns:
-        bool: True if both TC3 and TC4 percentages are within bounds.
-    """
-    tc3_valid = validator.tc_bandwidth_bound(bw_data['tc3_percentage'], 3)
-    tc4_valid = validator.tc_bandwidth_bound(bw_data['tc4_percentage'], 4)
-
-    return tc3_valid and tc4_valid
-
-
 def run_bandwidth_distribution_test(cfg, set_tc_mapping):
     """
     Runs parallel bandwidth measurements for both TCs and collects results.
@@ -395,9 +379,10 @@ def run_bandwidth_distribution_test(cfg, set_tc_mapping):
     test_name = "with TC mapping" if set_tc_mapping else "without TC mapping"
     print_bandwidth_results(bw_data, test_name)
 
-    verify_total_bandwidth(bw_data, cfg.bw_validator)
+    verify_total_bandwidth(bw_data, cfg.traffic_bw_validator)
 
-    return check_bandwidth_distribution(bw_data, cfg.bw_validator)
+    return cfg.tc_bw_validator.bound({"tc3": bw_data['tc3_percentage'],
+                                     "tc4": bw_data['tc4_percentage']})
 
 
 def test_no_tc_mapping_bandwidth(cfg):
@@ -441,7 +426,8 @@ def main() -> None:
         if not cfg.pci:
             raise KsftSkipEx("Could not get PCI address of the interface")
 
-        cfg.bw_validator = BandwidthValidator()
+        cfg.traffic_bw_validator = BandwidthValidator({"total": 1})
+        cfg.tc_bw_validator = BandwidthValidator({"tc3": 20, "tc4": 80})
 
         cases = [test_no_tc_mapping_bandwidth, test_tc_mapping_bandwidth]
 
-- 
2.38.1