Re: Regarding port numbers assigned by DPDK for PCI devices

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

2024-07-29 22:18 (UTC+0530), Prashant Upadhyaya:
> Hi,
> 
> I have 4 ethernet interfaces available as PCI devices.
> The PCI addresses are known.
> When I start my DPDK application, it starts up properly and assigns the
> port numbers to them as 0, 1, 2, 3 expectedly.
> 
> However, is there a way I can force that a particular PCI address should be
> identified as port 0 by DPDK, another one as port 1 and so forth ?
> Does passing the arguments like -a <address1> -a <address2> to rte_eal_init
> ensure that, or is there any other way, or is there no way ?
> 
> I am on 24.03
> 
> Regards
> -Prashant

Hi,

Why do you need specific port numbers assigned to devices?

If you're going to use devices for different purposes,
you'd better have an application-level configuration
to specify PCI addresses to use for each purpose.
Iterate devices to match the address and find the port number.

It is also possible to disable automatic probing with "-a 0:0.0",
then to use rte_dev_probe() + rte_dev_event_callback_register()
to add devices and to get their port numbers.
However, this API, strictly speaking, does not guarantee
that the numbers will be assigned sequentially.
One advantage of using hot-plug is that you can build devargs
from within the application (or from configuration).

Refer to "rte_dev.h" in any case.
Multiple "-a" don't work the way you've described.