Re: [dpdk-dev] [PATCH v2 04/11] examples/l3fwd: add ethdev setup based on eventdev

[Nipun Gupta <nipun.gupta@nxp.com>]

> -----Original Message-----
> From: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>
> Sent: Thursday, January 2, 2020 11:52 AM
> To: Nipun Gupta <nipun.gupta@nxp.com>; Jerin Jacob Kollanukkaran
> <jerinj@marvell.com>; Marko Kovacevic <marko.kovacevic@intel.com>; Ori
> Kam <orika@mellanox.com>; Bruce Richardson
> <bruce.richardson@intel.com>; Radu Nicolau <radu.nicolau@intel.com>;
> Akhil Goyal <akhil.goyal@nxp.com>; Tomasz Kantecki
> <tomasz.kantecki@intel.com>; Sunil Kumar Kori <skori@marvell.com>;
> Hemant Agrawal <hemant.agrawal@nxp.com>
> Cc: dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v2 04/11] examples/l3fwd: add ethdev setup
> based on eventdev
> 
> >> >&local_port_conf);
> >> >> +		if (ret < 0)
> >> >> +			rte_exit(EXIT_FAILURE,
> >> >> +				 "Cannot configure device: err=%d,
> >> >> port=%d\n",
> >> >> +				 ret, port_id);
> >> >> +
> >> >
> >> >We should be using number of RX queues as per the config option
> >> >provided in the arguments.
> >> >L3fwd is supposed to support multiple queue. Right?
> >>
> >> The entire premise of using event device is to showcase packet
> >scheduling to
> >> cores
> >> without the need for splitting packets across multiple queues.
> >>
> >> Queue config is ignored when event mode is selected.
> >
> >For atomic queues, we have single queue providing packets to a single
> >core at a time till processing on that core is completed, irrespective of
> >the flows on that hardware queue.
> >And multiple queues are required to distribute separate packets on
> >separate cores, with these atomic queues maintaining the ordering and
> >not scheduling on other core, until processing core has completed its
> >job.
> >To have this solution generic, we should also take config parameter -
> >(port, number of queues) to enable multiple ethernet RX queues.
> >
> 
> Not sure I follow we connect Rx queue to an event queue which is then
> linked to multiple event ports which are polled on
> by respective cores.

This is what we too support, but with atomic queue case the scenario gets little complex.
Each atomic queue can be scheduled only to one event port at a time, until all the events from
that event port are processed. Then only it can move to other event port.

To have separate event ports process packets at same time in atomic scenario, multiple queues
are required. As l3fwd supports multiple queues, it seems legitimate to add the support.

Thanks,
Nipun

> How would increasing Rx queues help? Distributing flows from single event
> queue to multiple event ports is the responsibility
> of Event device as per spec.
> Does DPAA/2 function differently?
> 
> Regards,
> Pavan.
> 
> >Regards,
> >Nipun
> >
> >>
> >> >
> >> >Regards,
> >> >Nipun
> >> >
> >>
> >> Regards,
> >> Pavan.