[Patch net 07/12] selftests/tc-testing: Add a test case for FQ_CODEL with HTB parent

Cong Wang
2025-03-20T23:25:57Z

Add a test case for FQ_CODEL with HTB parent to verify packet drop
behavior when the queue becomes empty. This helps ensure proper
notification mechanisms between qdiscs.

Note this is best-effort, it is hard to play with those parameters
perfectly to always trigger ->qlen_notify().

Cc: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
.../tc-testing/tc-tests/infra/qdiscs.json | 33 ++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json b/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json
index 9044ac054167..06cb2c3c577e 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json
@@ -126,5 +126,36 @@
"$TC qdisc del dev $DUMMY root handle 1: drr",
"$IP addr del 10.10.10.10/24 dev $DUMMY"
]
- }
+ },
+ {
+ "id": "a4bb",
+ "name": "Test FQ_CODEL with HTB parent - force packet drop with empty queue",
+ "category": [
+ "qdisc",
+ "fq_codel",
+ "htb"
+ ],
+ "plugins": {
+ "requires": "nsPlugin"
+ },
+ "setup": [
+ "$IP link set dev $DUMMY up || true",
+ "$IP addr add 10.10.10.10/24 dev $DUMMY || true",
+ "$TC qdisc add dev $DUMMY handle 1: root htb default 10",
+ "$TC class add dev $DUMMY parent 1: classid 1:10 htb rate 1kbit",
+ "$TC qdisc add dev $DUMMY parent 1:10 handle 10: fq_codel memory_limit 1 flows 1 target 0.1ms interval 1ms",
+ "$TC filter add dev $DUMMY parent 1: protocol ip prio 1 u32 match ip protocol 1 0xff flowid 1:10",
+ "ping -c 5 -f -I $DUMMY 10.10.10.1 > /dev/null || true",
+ "sleep 0.1"
+ ],
+ "cmdUnderTest": "$TC -s qdisc show dev $DUMMY",
+ "expExitCode": "0",
+ "verifyCmd": "$TC -s qdisc show dev $DUMMY | grep -A 5 'qdisc fq_codel'",
+ "matchPattern": "dropped [1-9][0-9]*",
+ "matchCount": "1",
+ "teardown": [
+ "$TC qdisc del dev $DUMMY handle 1: root",
+ "$IP addr del 10.10.10.10/24 dev $DUMMY || true"
+ ]
+ }
]
--
2.34.1