[dpdk-dev] [PATCH] net/i40e: enable statistic reset for VF

[Vincent Jardin]

Le 17 mars 2017 11:15:22 AM Thomas Monjalon <thomas.monjalon at 6wind.com> a 
écrit :

> 2017-03-17 09:45, Zhang, Helin:
>>From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
>> >2017-03-17 03:28, Zhang, Helin:
>> >> From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
>> >> > 2017-02-23 13:27, Qi Zhang:
>> >> > >  static void
>> >> > > +i40evf_dev_stats_reset(struct rte_eth_dev *dev) {
>> >> > > +	struct i40e_vf *vf = I40EVF_DEV_PRIVATE_TO_VF(dev->data-
>> >> > >dev_private);
>> >> > > +	/* only DPDK PF support this */
>> >> > > +	if (vf->version_major == I40E_DPDK_VERSION_MAJOR) {
>> >> > > +		if (i40evf_reset_statistics(dev))
>> >> > > +			PMD_DRV_LOG(ERR, "Reset statistics failed");
>> >> > > +	}
>> >> > > +}
>> >> >
>> >> > One more SR-IOV feature not supported with a Linux PF.
>> >> > The basic stats feature must be marked as partially supported in
>> >> > 	doc/guides/nics/features/i40e_vf.ini
>> >> > See also this email:
>> >> > 	http://dpdk.org/ml/archives/dev/2017-March/060063.html
>> >> >
>> >> > I wonder whether we should allow such divergence between PF
>> >> > implementations. Intel committed to avoid such fragmentation and
>> >> > keep the SR-IOV messaging standard but it does not happen.
>> >> > It is said that we must allow fast innovation in DPDK space.
>> >> > I agree but we should also target a good usability of the VF
>> >> > drivers, allowing to replace the PF implementations as needed.
>> >>
>> >> Hi Thomas
>> >>
>> >> I think I need to clarify a little bit here.
>> >> I think we will try our best, but I don't think we can commit. As they
>> >> are on totally different community, and of cause code repositories.
>
> What prevent you from submitting your code to the kernel community?
> Note that your statement does not respect the agreed policy:
> 	http://dpdk.org/ml/archives/dev/2017-January/055224.html
> 	http://dpdk.org/doc/guides/contributing/design.html#pf-and-vf-considerations
>
>> >> > Here is my suggestion: let's accept a VF feature only if the PF
>> >> > support is submitted to both dpdk.org and kernel.org mailing lists.
>> >> > I ask to add this topic to the next techboard meeting.
>> >>
>> >> Sorry, technically I disagree with this suggestion, as I don't 
>> understand why!
>> >> I was told DPDK is not Linux, and Linux is not DPDK. Why we want to
>> >> add this dependency on Linux PF host driver? And why just on PF/VF 
>> driver feature only?
>> >> I think if we can have any good innovative idea on DPDK first, why not
>> >> just have it on DPDK? Then Linux or even other OS/community/Company
>> >> can learn from DPDK and develop their own.
>> >
>> > It is really a general problem.
>> > Here you are adding a feature in a VF driver. But it does not work with
>> > some PF drivers.We have the same problem when adding a feature which
>> > does not work on BSD or on a CPU architecture.
>> > Generally speaking, we have a usability issue when a feature works only
>> > with a given environment.
>> > And it is worst in the SR-IOV case because a VM can migrate from an
>> > hypervisor (with a given PF) to another (and different) one.
>>
>> Yes, I understood that's the reality and the issue. But I don't think we 
>> can address it with your suggestion.
>> Linux is just one of the OS, as you said, FreeBSD, Windows, VMWare,  ...
>
> I am talking about migration from a KVM to another one.
> So BSD, Windows and VMware are irrelevant.
>
>> I'd suggest to start another discussion on the tech board to solve that 
>> problem, but not limit
>> adding new features. They are different topics and things, based on my 
>> understanding.
>
> Helin, you just want to add your new code and hide issues.
> You don't even bother to document the limitations or the partial support
> as I have suggested earlier.
> As a maintainer, I have to check the quality and the usability.
> I can tell you that I stack the promises "I will fix it later" and
> we are still waiting for a lot of them.
> That's why, even if you think it is not related, we need sometimes
> to block things until they are properly done and completed.

Please, can you bring it to the next tech board? This dispersion of VF/PF 
make the DPDK unusable into open products with many parties since behavior 
becomes VF/PF specific.

Thank you,