RE: [PATCH v4 0/4] Introduce Topology NUMA grouping for lcores

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> Sent: Thursday, 13 February 2025 09.34
> 
> 13/02/2025 04:09, Varghese, Vipin:
> > [AMD Official Use Only - AMD Internal Distribution Only]
> >
> > Adding Thomas and Ajit to the loop.
> >
> > Hi Ajit, we have been using the patch series for identifying the
> topology and getting l3 cache id for populating the steering tag for
> Device Specific Model & MSI-x driven af-xdp for the experimental STAG
> firmware on Thor.

Excellent. A real life example use case helps the review process a lot!

> >
> > Hence current use of topology library helps in
> > 1. workload placement in same Cache or IO domain
> > 2. populating id for MSIx or Device specific model for steering tags.
> >
> > Thomas and Ajith can we get some help to get this mainline too?
> 
> Yes, sorry the review discussions did not start.
> It has been forgotten.

I think the topology/domain API in the EAL should be co-designed with the steering tag API in the ethdev library, so the design can be reviewed/discussed in its entirety.

To help the review discussion, please consider describing the following:
Which APIs are for slow path, and which are for fast path?
Which APIs are "must have", i.e. core to making it work at all, and which APIs are "nice to have", i.e. support APIs to ease use of the new features?

I haven't looked at the hwloc library's API; but I guess these new EAL functions are closely related. Is it a thin wrapper around the hwloc library, or is it very different?