Re: [PATCH net-next v12 00/13] Add support for PSE budget evaluation strategy

[Gal Pressman]

On 09/06/2025 17:03, Kory Maincent wrote:
> Le Mon, 9 Jun 2025 14:03:46 +0300,
> Gal Pressman <gal@xxxxxxxxxx> a écrit :
> 
>> On 09/06/2025 11:36, Kory Maincent wrote:
>>> Le Sun, 8 Jun 2025 09:17:59 +0300,
>>> Gal Pressman <gal@xxxxxxxxxx> a écrit :
>>>   
>>>> On 28/05/2025 10:31, Paolo Abeni wrote:  
>>  [...]  
>>>>
>>>> Are all new uapi changes expected to come with a test that exercises the
>>>> functionality?  
>>>
>>> I don't think so and I don't think it is doable for now on PSE. There is
>>> nothing that could get the PSE control of a dummy PSE controller driver. We
>>> need either the support for a dummy PHY driver similarly to netdevsim or
>>> the support for the MDI ports.
>>> By luck Maxime Chevallier is currently working on both of these tasks and
>>> had already sent several times the patch series for the MDI port support.
>>>   
>>
>> We shouldn't rule it out so quickly, testing is important, let's try to
>> accommodate to our rules.
>>
>> Why can't this be tested on real hardware using a drivers/net/hw
>> selftest? The test can skip if it lacks the needed hardware.
>> Or rebase this over Maxime's work?
> 
> How should I do it if I need to use ethtool to test it? It is a vicious circle
> as ethtool need this to be merge before supporting it.
> Would it be ok to accept it like that and wait for ethtool support to add the
> selftest?
> Otherwise I could test it through ynl python command but there is no similar
> cases in the selftest.

I think that in theory the userspace patches need to be posted together
with the kernel, from maintainer-netdev.rst:

	User space code exercising kernel features should be posted
	alongside kernel patches. This gives reviewers a chance to see
	how any new interface is used and how well it works.

I am not sure if that's really the case though.

> 
> Nevertheless, it would have been nicer to point this out earlier in the series.

I agree, we also encountered the same thing :\...
I tried to convince the maintainer [1] that this needs to be documented
more clearly, but got ignored.

The current rule we have is:
"Broadly, any new uAPI should come with tests which exercise the
functionality."

[1]
https://lore.kernel.org/all/3a3ce4c2-5cc1-4deb-be47-d936b61c42c4@xxxxxxxxxx/