[PATCH v2 net 0/2] selftests: drv-net: Fix issues in devlink_rate_tc_bw.py

[PATCH v2 net 0/2] selftests: drv-net: Fix issues in devlink_rate_tc_bw.py

[Carolina Jubran]

This series fixes issues in devlink_rate_tc_bw.py selftest that made
its checks unreliable and its documentation inconsistent with the
actual configuration.

V2:
- Dropped the patch that relaxed the total bandwidth check. Jakub
  suggested addressing the instability with interval-based measurement
  and by migrating to load.py. That will be handled in a follow-up.
- Link to V1: https://lore.kernel.org/netdev/20250831080641.1828455-1-cjubran@nvidia.com/

Thanks

Carolina Jubran (2):
  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

 .../drivers/net/hw/devlink_rate_tc_bw.py      | 100 ++++++++----------
 1 file changed, 43 insertions(+), 57 deletions(-)

-- 
2.38.1

[PATCH v2 net 1/2] 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.

Fixes: 23ca32e4ead4 ("selftests: drv-net: Add test for devlink-rate traffic class bandwidth distribution")
Tested-by: Carolina Jubran <cjubran@nvidia.com>
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 ead6784d1910..4da91e3292bf 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%
 
@@ -413,10 +413,10 @@ 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):
@@ -430,13 +430,13 @@ 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 v2 net 2/2] 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.

Fixes: 23ca32e4ead4 ("selftests: drv-net: Add test for devlink-rate traffic class bandwidth distribution")
Tested-by: Carolina Jubran <cjubran@nvidia.com>
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 4da91e3292bf..abc20bc4a34a 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
@@ -68,39 +68,35 @@ from lib.py import cmd, defer, ethtool, ip
 
 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):
@@ -364,38 +360,26 @@ 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 iperf3 tests for both TCs and collects results.
@@ -406,9 +390,10 @@ 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):
@@ -453,7 +438,8 @@ def main() -> None:
             raise KsftSkipEx("Could not get PCI address of the interface")
         cfg.require_cmd("iperf3", local=True, remote=True)
 
-        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

Re: [PATCH v2 net 1/2] selftests: drv-net: Fix and clarify TC bandwidth split in devlink_rate_tc_bw.py

[Simon Horman]

On Tue, Sep 09, 2025 at 01:13:52PM +0300, Carolina Jubran wrote:
> 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.
> 
> Fixes: 23ca32e4ead4 ("selftests: drv-net: Add test for devlink-rate traffic class bandwidth distribution")
> Tested-by: Carolina Jubran <cjubran@nvidia.com>
> Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
> Reviewed-by: Nimrod Oren <noren@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH v2 net 2/2] selftests: drv-net: Fix tolerance calculation in devlink_rate_tc_bw.py

[Simon Horman]

On Tue, Sep 09, 2025 at 01:13:53PM +0300, Carolina Jubran wrote:
> 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.
> 
> Fixes: 23ca32e4ead4 ("selftests: drv-net: Add test for devlink-rate traffic class bandwidth distribution")
> Tested-by: Carolina Jubran <cjubran@nvidia.com>
> Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
> Reviewed-by: Nimrod Oren <noren@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH v2 net 0/2] selftests: drv-net: Fix issues in devlink_rate_tc_bw.py

[Simon Horman]

On Tue, Sep 09, 2025 at 01:13:51PM +0300, Carolina Jubran wrote:
> This series fixes issues in devlink_rate_tc_bw.py selftest that made
> its checks unreliable and its documentation inconsistent with the
> actual configuration.
> 
> V2:
> - Dropped the patch that relaxed the total bandwidth check. Jakub
>   suggested addressing the instability with interval-based measurement
>   and by migrating to load.py. That will be handled in a follow-up.
> - Link to V1: https://lore.kernel.org/netdev/20250831080641.1828455-1-cjubran@nvidia.com/
> 
> Thanks
> 
> Carolina Jubran (2):
>   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
> 
>  .../drivers/net/hw/devlink_rate_tc_bw.py      | 100 ++++++++----------
>  1 file changed, 43 insertions(+), 57 deletions(-)

Hi Carolina,

It isn't strictly related to these changes.
But CI flaggs that devlink_rate_tc_bw.py should
be present in the Makefile for in the same directory.

Given the wildcard in the Makefile I'm unsure if that
is true or not. Could you take a look?