[PATCH net-next v12 8/8] selftests: drv-net: Add test for devlink-rate traffic class bandwidth distribution

From: Carolina Jubran cjubran@nvidia.com

This test suite validates the functionality of the devlink-rate API for traffic class (TC) bandwidth allocation. It ensures that bandwidth can be distributed between different traffic classes as configured, and verifies that explicit TC-to-queue mapping is required for the allocation to be effective.

The first test (test_no_tc_mapping_bandwidth) is marked as expected failure on mlx5, since the hardware automatically enforces traffic class separation by dynamically moving queues to the correct TC scheduler, even without explicit TC-to-queue mapping configuration.

Test output on mlx5: 1..2 # Created VF interface: eth5 # Created VLAN eth5.101 on eth5 with tc 3 and IP 198.51.100.2 # Created VLAN eth5.102 on eth5 with tc 4 and IP 198.51.100.10 # Set representor eth4 up and added to bridge # Bandwidth check results without TC mapping: # TC 3: 0.19 Gbits/sec # TC 4: 0.76 Gbits/sec # Total bandwidth: 0.95 Gbits/sec # TC 3 percentage: 20.0% # TC 4 percentage: 80.0% ok 1 devlink_rate_tc_bw.test_no_tc_mapping_bandwidth # XFAIL Bandwidth matched 80/20 split without TC mapping # Created VF interface: eth5 # Created VLAN eth5.101 on eth5 with tc 3 and IP 198.51.100.2 # Created VLAN eth5.102 on eth5 with tc 4 and IP 198.51.100.10 # Set representor eth4 up and added to bridge # Bandwidth check results with TC mapping: # TC 3: 0.21 Gbits/sec # TC 4: 0.78 Gbits/sec # Total bandwidth: 0.98 Gbits/sec # TC 3 percentage: 21.1% # TC 4 percentage: 78.9% # Bandwidth is distributed as 80/20 with TC mapping ok 2 devlink_rate_tc_bw.test_tc_mapping_bandwidth # Totals: pass:1 fail:0 xfail:1 xpass:0 skip:0 error:0

Signed-off-by: Carolina Jubran cjubran@nvidia.com Reviewed-by: Cosmin Ratiu cratiu@nvidia.com Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Mark Bloch mbloch@nvidia.com --- Hi Jakub, You can find the iproute2 patch here: https://lore.kernel.org/netdev/20250625182545.86994-1-mbloch@nvidia.com/

.../drivers/net/hw/devlink_rate_tc_bw.py | 466 ++++++++++++++++++ .../drivers/net/hw/lib/py/__init__.py | 2 +- .../selftests/drivers/net/lib/py/__init__.py | 2 +- .../testing/selftests/net/lib/py/__init__.py | 2 +- tools/testing/selftests/net/lib/py/ynl.py | 5 + 5 files changed, 474 insertions(+), 3 deletions(-) create mode 100755 tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py

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 new file mode 100755 index 000000000000..820d8a03becc --- /dev/null +++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py @@ -0,0 +1,466 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 + +""" +Devlink Rate TC Bandwidth Test Suite +=================================== + +This test suite verifies the functionality of devlink-rate traffic class (TC) +bandwidth distribution in a virtualized environment. The tests validate that +bandwidth can be properly allocated between different traffic classes and +that TC mapping works as expected. + +Test Environment: +---------------- +- Creates 1 VF +- Establishes a bridge connecting the VF representor and the uplink representor +- Sets up 2 VLAN interfaces on the VF with different VLAN IDs (101, 102) +- Configures different traffic classes (TC3 and TC4) for each VLAN + +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 + mapping + - Expected: Bandwidth should NOT be distributed as 80/20 + +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 + +Bandwidth Distribution: +---------------------- +- TC3 (VLAN 101): Configured for 80% of total bandwidth +- TC4 (VLAN 102): Configured for 20% of total bandwidth +- Total bandwidth: 1Gbps +- Tolerance: +-12% + +Hardware-Specific Behavior (mlx5): +-------------------------- +mlx5 hardware enforces traffic class separation by ensuring that each transmit +queue (SQ) is associated with a single TC. If a packet is sent on a queue that +doesn't match the expected TC (based on DSCP or VLAN priority and hypervisor-set +mapping), the hardware moves the queue to the correct TC scheduler to preserve +traffic isolation. + +This behavior means that even without explicit TC-to-queue mapping, bandwidth +enforcement may still appear to work���because the hardware dynamically adjusts +the scheduling context. However, this can lead to performance issues in high +rates and HOL blocking if traffic from different TCs is mixed on the same queue. +""" + +import json +import os +import subprocess +import threading +import time + +from lib.py import ksft_pr, ksft_run, ksft_exit +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 + + +class BandwidthValidator: + """ + Validates bandwidth totals and per-TC shares against expected values + with a tolerance. + """ + + def __init__(self): + 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, + } + + def min_expected(self, value): + """Calculates the minimum acceptable value based on tolerance.""" + return value - (value * 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) + + def tc_bandwidth_bound(self, value, tc_ix): + """ + Returns True if the given bandwidth value is within tolerance + for the TC's expected bandwidth. + """ + expected = self.tc_expected_percent[tc_ix] + return self.bound(expected, value) + + +def setup_vf(cfg, set_tc_mapping=True): + """ + Sets up a VF on the given network interface. + + Enables SR-IOV and switchdev mode, brings the VF interface up, + and optionally configures TC mapping using mqprio. + """ + try: + cmd(f"devlink dev eswitch set pci/{cfg.pci} mode switchdev") + defer(cmd, f"devlink dev eswitch set pci/{cfg.pci} mode legacy") + 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") + except Exception as exc: + raise KsftSkipEx(f"Failed to enable SR-IOV on {cfg.ifname}") from exc + + time.sleep(2) + vf_ifc = (os.listdir( + f"/sys/class/net/{cfg.ifname}/device/virtfn0/net") or [None])[0] + if vf_ifc: + ip(f"link set dev {vf_ifc} up") + else: + raise KsftSkipEx("VF interface not found") + if set_tc_mapping: + cmd(f"tc qdisc add dev {vf_ifc} root handle 5 mqprio mode dcb hw 1 num_tc 8") + + return vf_ifc + + +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"}, + ] + + for config in vlan_configs: + vlan_dev = f"{vf_ifc}.{config['vlan_id']}" + ip(f"link add link {vf_ifc} name {vlan_dev} type vlan id {config['vlan_id']}") + ip(f"addr add {config['ip']}/29 dev {vlan_dev}") + ip(f"link set dev {vlan_dev} up") + ip(f"link set dev {vlan_dev} type vlan egress-qos-map 0:{config['tc']}") + ksft_pr(f"Created VLAN {vlan_dev} on {vf_ifc} with tc {config['tc']} and IP {config['ip']}") + + +def get_vf_info(cfg): + """ + Finds the VF representor interface and devlink port index + for the given PCI device used in the test environment. + """ + cfg.vf_representor = None + cfg.vf_port_index = None + out = subprocess.check_output(["devlink", "-j", "port", "show"], encoding="utf-8") + ports = json.loads(out)["port"] + + for port_name, props in ports.items(): + netdev = props.get("netdev") + + if (port_name.startswith(f"pci/{cfg.pci}/") and + props.get("vfnum") == 0): + cfg.vf_representor = netdev + cfg.vf_port_index = int(port_name.split("/")[-1]) + break + + +def setup_bridge(cfg): + """ + Creates and configures a Linux bridge, with both the uplink + and VF representor interfaces attached to it. + """ + bridge_name = f"br_{os.getpid()}" + ip(f"link add name {bridge_name} type bridge") + defer(cmd, f"ip link del name {bridge_name} type bridge") + + ip(f"link set dev {cfg.ifname} master {bridge_name}") + + rep_name = cfg.vf_representor + if rep_name: + ip(f"link set dev {rep_name} master {bridge_name}") + ip(f"link set dev {rep_name} up") + ksft_pr(f"Set representor {rep_name} up and added to bridge") + else: + raise KsftSkipEx("Could not find representor for the VF") + + ip(f"link set dev {bridge_name} up") + + +def setup_devlink_rate(cfg): + """ + Configures devlink rate tx_max and traffic class bandwidth for the VF. + """ + port_index = cfg.vf_port_index + if port_index is None: + raise KsftSkipEx("Could not find VF port index") + try: + cfg.devnl.rate_set({ + "bus-name": "pci", + "dev-name": cfg.pci, + "port-index": port_index, + "rate-tx-max": 125000000, + "rate-tc-bws": [ + {"rate-tc-index": 0, "rate-tc-bw": 0}, + {"rate-tc-index": 1, "rate-tc-bw": 0}, + {"rate-tc-index": 2, "rate-tc-bw": 0}, + {"rate-tc-index": 3, "rate-tc-bw": 20}, + {"rate-tc-index": 4, "rate-tc-bw": 80}, + {"rate-tc-index": 5, "rate-tc-bw": 0}, + {"rate-tc-index": 6, "rate-tc-bw": 0}, + {"rate-tc-index": 7, "rate-tc-bw": 0}, + ] + }) + except NlError as exc: + if exc.error == 95: # EOPNOTSUPP + raise KsftSkipEx("devlink rate configuration is not supported on the VF") from exc + raise KsftFailEx(f"rate_set failed on VF port {port_index}") from exc + + +def setup_remote_server(cfg): + """ + Sets up VLAN interfaces and starts iperf3 servers on the remote side. + """ + remote_dev = cfg.remote_ifname + vlan_ids = [101, 102] + remote_ips = ["198.51.100.1", "198.51.100.9"] + + for vlan_id, ip_addr in zip(vlan_ids, remote_ips): + vlan_dev = f"{remote_dev}.{vlan_id}" + cmd(f"ip link add link {remote_dev} name {vlan_dev} " + 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. + """ + vf_ifc = setup_vf(cfg, set_tc_mapping) + ksft_pr(f"Created VF interface: {vf_ifc}") + + setup_vlans_on_vf(vf_ifc) + + get_vf_info(cfg) + setup_bridge(cfg) + + setup_devlink_rate(cfg) + setup_remote_server(cfg) + time.sleep(2) + + +def run_iperf_client(server_ip, local_ip, barrier, min_expected_gbps=0.1): + """ + Runs a single iperf3 client instance, binding to the given local IP. + Waits on a barrier to synchronize with other threads. + """ + 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 + + +def run_bandwidth_test(): + """ + Launches iperf3 client threads 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) + + 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), + ] + + results = {} + threads = [] + start_barrier = threading.Barrier(len(vf_vlan_data)) + + 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) + ) + thread.start() + threads.append(thread) + + for thread in threads: + thread.join() + + for tc_ix, tc_bw in results.items(): + if tc_bw is None: + raise KsftFailEx("iperf3 client failed; cannot evaluate bandwidth") + + return results + +def calculate_bandwidth_percentages(results): + """ + Calculates the percentage of total bandwidth received by TC3 and TC4. + """ + if 3 not in results or 4 not in results: + raise KsftFailEx(f"Missing expected TC results in {results}") + + tc3_bw = results[3] + tc4_bw = results[4] + total_bw = tc3_bw + tc4_bw + tc3_percentage = (tc3_bw / total_bw) * 100 + tc4_percentage = (tc4_bw / total_bw) * 100 + + return { + 'tc3_bw': tc3_bw, + 'tc4_bw': tc4_bw, + 'tc3_percentage': tc3_percentage, + 'tc4_percentage': tc4_percentage, + 'total_bw': total_bw + } + + +def print_bandwidth_results(bw_data, test_name): + """ + Prints bandwidth measurements and TC usage summary for a given test. + """ + ksft_pr(f"Bandwidth check results {test_name}:") + ksft_pr(f"TC 3: {bw_data['tc3_bw']:.2f} Gbits/sec") + ksft_pr(f"TC 4: {bw_data['tc4_bw']:.2f} Gbits/sec") + ksft_pr(f"Total bandwidth: {bw_data['total_bw']:.2f} Gbits/sec") + ksft_pr(f"TC 3 percentage: {bw_data['tc3_percentage']:.1f}%") + ksft_pr(f"TC 4 percentage: {bw_data['tc4_percentage']:.1f}%") + + +def verify_total_bandwidth(bw_data, validator): + """ + Ensures the total measured bandwidth falls within the acceptable tolerance. + """ + total = bw_data['total_bw'] + + if validator.bound(validator.expected_total_gbps, total): + return + + if total < validator.total_min_expected: + 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"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)" + ) + + +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. + """ + setup_test_environment(cfg, set_tc_mapping) + bandwidths = run_bandwidth_test() + 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) + + verify_total_bandwidth(bw_data, cfg.bw_validator) + + return check_bandwidth_distribution(bw_data, cfg.bw_validator) + + +def test_no_tc_mapping_bandwidth(cfg): + """ + Verifies that bandwidth is not split 80/20 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" + is_mlx5 = "driver: mlx5" in ethtool(f"-i {cfg.ifname}").stdout + + if run_bandwidth_distribution_test(cfg, set_tc_mapping=False): + if is_mlx5: + raise KsftXfailEx(fail_bw_msg) + raise KsftFailEx(fail_bw_msg) + if is_mlx5: + raise KsftFailEx("mlx5 behavior changed:" + pass_bw_msg) + ksft_pr(pass_bw_msg) + + +def test_tc_mapping_bandwidth(cfg): + """ + Verifies that bandwidth is correctly split 80/20 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") + else: + raise KsftFailEx("Bandwidth did not match 80/20 split with TC mapping") + + +def main() -> None: + """ + Main entry point for running the test cases. + """ + with NetDrvEpEnv(__file__, nsim_test=False) as cfg: + cfg.devnl = DevlinkFamily() + + cfg.pci = os.path.basename( + os.path.realpath(f"/sys/class/net/{cfg.ifname}/device") + ) + if not cfg.pci: + raise KsftSkipEx("Could not get PCI address of the interface") + cfg.require_cmd("iperf3") + cfg.require_cmd("iperf3", remote=True) + + cfg.bw_validator = BandwidthValidator() + + cases = [test_no_tc_mapping_bandwidth, test_tc_mapping_bandwidth] + + ksft_run(cases=cases, args=(cfg,)) + ksft_exit() + + +if __name__ == "__main__": + main() 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 56ff11074b55..1462a339a74b 100644 --- a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py +++ b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py @@ -13,7 +13,7 @@ try:

# Import one by one to avoid pylint false positives from net.lib.py import EthtoolFamily, NetdevFamily, NetshaperFamily, \ - NlError, RtnlFamily + NlError, RtnlFamily, DevlinkFamily from net.lib.py import CmdExitFailure from net.lib.py import bkg, cmd, defer, ethtool, fd_read_timeout, ip, \ rand_port, tool, wait_port_listen diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py index 9ed1d8f70524..fce5d9218f1d 100644 --- a/tools/testing/selftests/drivers/net/lib/py/__init__.py +++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py @@ -12,7 +12,7 @@ try:

# Import one by one to avoid pylint false positives from net.lib.py import EthtoolFamily, NetdevFamily, NetshaperFamily, \ - NlError, RtnlFamily + NlError, RtnlFamily, DevlinkFamily from net.lib.py import CmdExitFailure from net.lib.py import bkg, cmd, defer, ethtool, fd_read_timeout, ip, \ rand_port, tool, wait_port_listen diff --git a/tools/testing/selftests/net/lib/py/__init__.py b/tools/testing/selftests/net/lib/py/__init__.py index 8697bd27dc30..02be28dcc089 100644 --- a/tools/testing/selftests/net/lib/py/__init__.py +++ b/tools/testing/selftests/net/lib/py/__init__.py @@ -6,4 +6,4 @@ from .netns import NetNS, NetNSEnter from .nsim import * from .utils import * from .ynl import NlError, YnlFamily, EthtoolFamily, NetdevFamily, RtnlFamily, RtnlAddrFamily -from .ynl import NetshaperFamily +from .ynl import NetshaperFamily, DevlinkFamily diff --git a/tools/testing/selftests/net/lib/py/ynl.py b/tools/testing/selftests/net/lib/py/ynl.py index 6329ae805abf..2b3a61ea3bfa 100644 --- a/tools/testing/selftests/net/lib/py/ynl.py +++ b/tools/testing/selftests/net/lib/py/ynl.py @@ -56,3 +56,8 @@ class NetshaperFamily(YnlFamily): def __init__(self, recv_size=0): super().__init__((SPEC_PATH / Path('net_shaper.yaml')).as_posix(), schema='', recv_size=recv_size) + +class DevlinkFamily(YnlFamily): + def __init__(self, recv_size=0): + super().__init__((SPEC_PATH / Path('devlink.yaml')).as_posix(), + schema='', recv_size=recv_size)