[dpdk-dev] [PATCH] ethdev: ensure consistent port id assignment

[Tootoonchian, Amin]

Inline:

> > This is the intended behavior with this patch. Ports are to be created
> > only by the primary process. This is required for correct operation
> > IMO, because if we allow secondary processes to create ports
> > dynamically (and locally use conflicting port ids) without any
> > synchronization mechanism, they're guaranteed to overwrite each other's
> rte_eth_dev_data.
> 
> Thanks Amin for clarification,
> I had another approach, that rte_eth_devices and rte_eth_dev_data should have
> different offset of port_id and secondary process can also add devices.

That wouldn't work without some rather intrusive changes. As of now, rte_eth_dev_data includes port_id and therefore should be consistent across processes. 

> as I now understand with this patch we will not be able do something like:
> Primary:
> ./test-pmd -c 0xf  -n 4 --socket-mem='512,0'  -w 03:00.1 -w 03:00.0
> 				--proc-type=primary --file-prefix=xz1 -- -i
> Secondary:
> ./test-pmd -c 0xf0 --socket-mem='512,0' -n 4 -v -b 03:00.1 -b 03:00.0 --vdev
> 'eth_pcap0,rx_pcap=/var/log/device1.pcap,tx_pcap=/var/log/device2.pcap'
> --proc-type=secondary --file-prefix=xz1 -- -i
> 
> Because secondary processes "Ports are to be created only by the primary
> process"?

Right, that wouldn't work.

Amin