Re: [PATCH mptcp-next 3/3] DO-NOT-MERGE: mptcp: sched: penalise counters

[Matthieu Baerts <matttbe@kernel.org>]

Hi Shardul,

Thank you for your reply!

On 07/08/2026 17:19, Shardul Bankar wrote:
> Hi Matt,
> 
> On Wed, 2026-07-29 at 13:50 +0200, Matthieu Baerts wrote:
>> Hi Shardul,
>>
>> On 26/07/2026 07:55, Shardul Bankar wrote:
>>> Instrumentation for validating the two preceding patches; not for
>>> merge.
>>>
>>> Adds two MPTcpExt SNMP counters:
>>> - CwndPenalized: times a subflow cwnd was actually halved;
>>> - PenalCandidate: times the rate trigger picked a slow subflow.
>>
>> I think at least the first counter is interesting, probably the
>> second
>> one as well, no?
>>
>> Generally, if you need counters during the development, they might be
>> needed to debug issues. But here with the scheduler, maybe the
>> tracing
>> are better. Did you use "trace_mptcp_subflow_get_send"?
>>
> 
> I did not. Looking at it now, it fires before the penalise decision and
> does not see the halving, so it would need a small extension (a new
> field, or a tracepoint at the halving point) to show what these
> counters show. Which would you prefer for v2: keep the DO-NOT-MERGE
> counters, or add that tracepoint? I will go with your call.

Maybe both?

If you can add a new field for the tracing, that would help with the
development. The MIB counter would help with the debugging.

Cheers,
Matt
-- 
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