[dpdk-dev] [PATCH v4 1/4] ethdev: add the API for getting burst mode information

[Jerin Jacob]

On Fri, Oct 25, 2019 at 9:15 PM Thomas Monjalon <thomas at monjalon.net> wrote:
>
> 25/10/2019 16:08, Ferruh Yigit:
> > On 10/25/2019 10:36 AM, Thomas Monjalon wrote:
> > > 15/10/2019 09:51, Haiyue Wang:
> > >> Some PMDs have more than one RX/TX burst paths, add the ethdev API
> > >> that allows an application to retrieve the mode information about
> > >> Rx/Tx packet burst such as Scalar or Vector, and Vector technology
> > >> like AVX2.
> > >
> > > I missed this patch. I and Andrew, maintainers of ethdev, were not CC'ed.
> > > Ferruh, I would expect to be Cc'ed and/or get a notification before merging.
> >
> > It has been discussed in the mail list and went through multiple discussions,
> > patch is out since the August, +1 to cc all maintainers I missed that part,
> > but when the patch is reviewed and there is no objection, why block the merge?
>
> I'm not saying blocking the merge.
> My bad is that I missed the patch and I am asking for help with a notification
> in this case. Same for Andrew I guess.
> Note: it is merged in master and I am looking to improve this feature.
>

> > >> +/**
> > >> + * Ethernet device RX/TX queue packet burst mode information structure.
> > >> + * Used to retrieve information about packet burst mode setting.
> > >> + */
> > >> +struct rte_eth_burst_mode {
> > >> +  uint64_t options;
> > >> +};
> > >
> > > Why a struct for an integer?
> >
> > Again by a request from me, to not need to break the API if we need to add more
> > thing in the future.
>
> I would replace it with a string. This is the most flexible API.

IMO, Probably, best of both worlds make a good option here,
as Haiyue suggested if we have an additional dev_specific[1] in structure.
and when a pass to the application, let common code make final string as
(options flags to string + dev_specific)

options flag can be zero if PMD does not have any generic flags nor
interested in such a scheme.
Generic flags will help at least to have some common code.

[1]
struct rte_eth_burst_mode {
        uint64_t options;
        char dev_specific[128]; /* PMD has specific burst mode information */
};