Re: Getting network port ID by ethdev port ID

[Thomas Monjalon <thomas@monjalon.net>]

05/06/2023 16:03, Ivan Malov:
> Hi Thomas,
> 
> Thanks for responding. Please see below.
> 
> On Mon, 5 Jun 2023, Thomas Monjalon wrote:
> 
> > Hello,
> >
> > 05/06/2023 15:09, Ivan Malov:
> >> Dear community,
> >>
> >> Is there any means in DPDK to discover relationship between
> >> network/physical ports of the given adapter/board and
> >> etdevs deployed in DPDK application on top of it?
> >>
> >> For example, in Linux, there are facilities like
> >>
> >>> /sys/class/net/<iface>/phys_port_name
> >>> /sys/class/net/<iface>/dev_port
> >>
> >> and
> >>
> >>> devlink port show
> >>
> >> Do we have something similar in DPDK?
> >
> > We can get the device name of a port:
> > 	rte_eth_dev_get_name_by_port()
> 
> I'm afraid this won't do. Consider the following example.
> Say, there's a NIC with two network ports and two PFs,
> 0000:01:00.0 and 0000:01:00.1. The user plugs these
> PFs to DPDK application. The resulting ethdev IDs
> are 0 and 1. If the user invokes the said API,
> they will get 0000:01:00.0 and 0000:01:00.1.
> But that's not what is really needed.
> 
> We seek a means to get the network port ID by
> ethdev ID. For example, something like this:
> - get_netport_by_ethdev(0) => 0
> - get_netport_by_ethdev(1) => 1
> 
> If two different PCI functions are associated with the
> same network port (0, for instance), this should be
> - get_netport_by_ethdev(0) => 0
> - get_netport_by_ethdev(1) => 0
> 
> Do we have something like that in DPDK?

No we don't have such underlying index.
I don't understand why it is needed.
To me the name is more informative than a number.


> >> If no, would the feature be worthwhile implementing?
> >
> > We may have discrepancies in different device classes.
> 
> I mean precisely "ethdev"s. I do realise, though, that
> an ethdev may be backed by a vdev (af_xdp, etc.) = in
> such cases the assumed "get_netport" method could
> just return (-ENOTSUP). What do you think?

Are you interested only in PCI devices? Looks limited.

> > Feel free to make a global status of device names.
> >
> Could you please elaborate on this?

I thought you wanted to have device name in all device classes.