[dpdk-dev] Instability of port ids

[Jay Rolette]

On Fri, May 17, 2019 at 1:46 PM Stephen Hemminger <
stephen at networkplumber.org> wrote:

> Several customers have reported similar issues with how the owned/stack
> device model
> works in DPDK. With failsafe/tap and VF or netvsc and VF there are DPDK
> ports which
> are marked as owned and therefore not visible.
>
> The problem is the application has to guess and workaround these port
> values in
> the port mask that gets passed in on command line. This means a working
> application
> has to modify its startup script to run on Azure. Worse the actual port
> values
> change based on the number of NIC's configured.
>
> Overall this is a nuisance for users. The whole DPDK port index concept is
> a bad
> design. In Linux/BSD there is ifindex, but few applications care, they all
> use names
> which is better. Very very few application care that eth1 is ifindex 4.
>
> The whole assignment of ports is a mess as well since it is based on probe
> order
> and that is based on PCI order, and not anything dependable. It gets worse
> with
> command line arguments, vdev, owned devices etc.
>
> All I can think of is that:
>   * DPDK network devices need to have human readable names. current PCI is
> not good.
>   * The names need to be repeatable/persistent. udev names are probably
> better than anything so far.
>     Or bsd style names but they end up being device dependent.
>   * The API to get from name to port needs to easy to use and the
> preferred method.
>   * All examples and documentation should avoid using port index directly.
>     You need port for fast rx/tx but setup should be by name.
>

+1 agree completely