[dpdk-dev] Querying for rte_flow support?

[Stephen Hemminger]

On Wed, 29 Sep 2021 20:52:43 +0200
Thomas Monjalon <thomas at monjalon.net> wrote:

> 29/09/2021 19:44, Stephen Hemminger:
> > Have a problem with auto-detecting whether device driver supports rte_flow.
> > 
> > Ideally in application would like to be able adapt to handle devices that
> > do rte_flow and those that do not.  If device does not support rte_flow,
> > then configure with RSS across multiple cores; if device does support rte_flow
> > then assign traffic to queue based on match (on MAC).
> > 
> > The problem is that there really is not a good API in DPDK for checking.
> > Most device drivers will not give the correct return to rte_flow_validate
> > unless the device is configured already, and some require device to be started.
> > In order to configure, the application has to choose how many queues to use
> > and that is the reason it wants to know if rte_flow will work!
> > 
> > The other alternative is looking at DPDK internal data structs to see
> > if device supports flow operations. That is not good, and causes more
> > issues in later releases.
> > 
> > Looks like rte_flow has a "chicken/egg problem" here.  
> 
> I think we just need to fix drivers implementation of rte_flow_validate().
> We must be able to validate a flow before starting the device.
> Which drivers are refusing such check?
> That's something we can check with some unit tests.
> 
> 

The issue is with Broadcom but I see it with others.
Mostly because they validate the queue id in the flow request.