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Message-ID: <20250831080641.1828455-3-cjubran@nvidia.com>
Date: Sun, 31 Aug 2025 11:06:40 +0300
From: Carolina Jubran <cjubran@...dia.com>
To: Shuah Khan <shuah@...nel.org>, Andrew Lunn <andrew+netdev@...n.ch>, "David
S . Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, "Jakub
Kicinski" <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
CC: Gal Pressman <gal@...dia.com>, Tariq Toukan <tariqt@...dia.com>, "Cosmin
Ratiu" <cratiu@...dia.com>, Nimrod Oren <noren@...dia.com>, Mark Bloch
<mbloch@...dia.com>, <linux-kernel@...r.kernel.org>,
<linux-kselftest@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: [PATCH 2/3] selftests: drv-net: Fix tolerance calculation in devlink_rate_tc_bw.py
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@...dia.com>
Signed-off-by: Carolina Jubran <cjubran@...dia.com>
Reviewed-by: Cosmin Ratiu <cratiu@...dia.com>
Reviewed-by: Nimrod Oren <noren@...dia.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
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