Re: [Patch net 08/12] selftests/tc-testing: Add a test case for CODEL with HTB parent

Victor Nogueira
2025-04-03T01:23:26Z

On 02/04/2025 21:40, Cong Wang wrote:
> On Sun, Mar 30, 2025 at 4:32 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>>
>> On Sun, Mar 30, 2025 at 06:05:06PM -0300, Victor Nogueira wrote:
>>> On 28/03/2025 17:35, Cong Wang wrote:
>>>> On Sun, Mar 23, 2025 at 07:48:39PM -0300, Victor Nogueira wrote:
>>>>> On 20/03/2025 20:25, Cong Wang wrote:
>>>>>> Add a test case for 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>
>>>>>
>>>>> Cong, can you double check this test?
>>>>> I ran all of your other tests and they all succeeded, however
>>>>> this one specifically is always failing:
>>>>
>>>> Interesting, I thought I completely fixed this before posting after several
>>>> rounds of playing with the parameters. I will double check it, maybe it
>>>> just becomes less reproducible.
>>>
>>> I see.
>>> I experimented with it a bit today and found out that changing the ping
>>> command to:
>>>
>>> ping -c 2 -i 0 -s 1500 -I $DUMMY 10.10.10.1 > /dev/null || true
>>>
>>> makes the test pass consistently (at least in my environment).
>>> So essentially just changing the "-s" option to 1500.
>>>
>>> If you could, please try it out as well.
>>> Maybe I just got lucky.
>>
>> Sure, I will change it to 1500.
>
> Hmm, it failed on my side:
>
> Test a4bd: Test CODEL with HTB parent - force packet drop with empty queue
> [...]

I see, this test seems to be very environment sensitive.
I think it will be better if we do what you suggested earlier.
It's not fair to stall this set because of this single test.
Can you resend your patches excluding this test?
I can try and figure this one out later so that we can
unblock.

cheers,
Victor