Re: [dpdk-dev] [PATCH] eventdev: fix device probe and remove for secondary process

["Varghese, Vipin" <vipin.varghese@intel.com>]

Thanks Jerin, agree with you on graceful shutdown in rc2.

> -----Original Message-----
> From: Jerin Jacob <jerinjacobk@gmail.com>
> Sent: Sunday, May 3, 2020 3:28 PM
> To: Varghese, Vipin <vipin.varghese@intel.com>
> Cc: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin Jacob
> Kollanukkaran <jerinj@marvell.com>; Burakov, Anatoly
> <anatoly.burakov@intel.com>; dpdk-dev <dev@dpdk.org>
> Subject: Re: [dpdk-dev] [PATCH] eventdev: fix device probe and remove for
> secondary process
> 
> On Sun, May 3, 2020 at 6:45 AM Varghese, Vipin <vipin.varghese@intel.com>
> wrote:
> >
> > Hi Pavan,
> >
> > Snipped
> >
> > > >> > >
> > > >> > > When probing event device in secondary process skip
> > > >> > > reinitializing the device data structure as it is already
> > > >> > > done in primary
> > > process.
> > > >> > >
> > > >> > > When removing event device in secondary process skip closing
> > > >> > > the event device as it should be done by primary process.
> > > >If primary has crashed or closed before secondary abnormally.
> > > >Should not close of secondary trigger removal of Eventdev services?
> > >
> > > Closing event device on exit of one secondary doesn’t make sense as
> > > there might be systems where there might be one primary and multiple
> > > secondaries and secondaries are spawned/destroyed on demand.
> > >
> > > Behavior of secondaries on primary process crash is undefined.
> > Absolutely true, there are work scenarios where primary configures ports
> and Eventdev queues-ports pair. It would be multiple secondaries which
> process packets via event dev. In such cases, when primary segfaults or crashes
> it will lead to undefined states.
> >
> > In such scenarios, would not it be preferer able for all secondaries to
> subscribe to service function like health check. If the primary is not alive
> anymore, then gracefully handle inflight events and events to dequeue. If this
> is right understanding, should not there be option in secondary to gracefully
> shut down it's worker queue and ports (rather than event device instance)?
> 
> The health check function may not be limited to eventdev, it must apply for all
> the subsystems in multiprocess mode if primary dies.
> Such features can be designed/agreed based on every subsystem in mind.
> For rc2, Let's have this bug fix. New features can be implemented after an
> agreement with all stakeholders wrt multi-process semantics which applicable
> for all subsystems.
> 
> 
> >
> > snipped