Re: [dpdk-dev] [PATCH 3/3] ethdev: add async queue-based flow rules operations

[Ori Kam <orika@nvidia.com>]

Hi Ajit,

> -----Original Message-----
> From: Ajit Khaparde <ajit.khaparde@broadcom.com>
> Sent: Wednesday, October 13, 2021 7:58 AM
> Subject: Re: [PATCH 3/3] ethdev: add async queue-based flow rules operations
> 
> On Tue, Oct 5, 2021 at 9:49 PM Alexander Kozyrev <akozyrev@nvidia.com> wrote:
> >
> > A new, faster, queue-based flow rules management mechanism is needed
> > for applications offloading rules inside the datapath. This
> > asynchronous and lockless mechanism frees the CPU for further packet
> > processing and reduces the performance impact of the flow rules
> > creation/destruction on the datapath. Note that queues are not
> > thread-safe and queue-based operations can be safely invoked without any locks from a single
> thread.
> >
> > The rte_flow_q_flow_create() function enqueues a flow creation to the
> > requested queue. It benefits from already configured resources and
> > sets unique values on top of item and action templates. A flow rule is
> > enqueued on the specified flow queue and offloaded asynchronously to the hardware.
> > The function returns immediately to spare CPU for further packet
> > processing. The application must invoke the rte_flow_q_dequeue()
> > function to complete the flow rule operation offloading, to clear the
> > queue, and to receive the operation status. The
> > rte_flow_q_flow_destroy() function enqueues a flow destruction to the requested queue.
> >
> > Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
> > Suggested-by: Ori Kam <orika@nvidia.com>
> > ---
> >  lib/ethdev/rte_flow.h | 288
> > ++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 288 insertions(+)
> >
> > diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h index
> > ba3204b17e..8cdffd8d2e 100644
> > --- a/lib/ethdev/rte_flow.h
> > +++ b/lib/ethdev/rte_flow.h
> > @@ -4298,6 +4298,13 @@ struct rte_flow_port_attr {
> >          * Version of the struct layout, should be 0.
> >          */
> >         uint32_t version;
> > +       /**
> > +        * Number of flow queues to be configured.
> > +        * Flow queues are used for asyncronous flow rule creation/destruction.
> > +        * The order of operations is not guaranteed inside a queue.
> > +        * Flow queues are not thread-safe.
> > +        */
> > +       uint16_t nb_queues;
> Will it matter if PMD can create a smaller set of queues? Or may be just one?
> Should the application set this based on get_infos_get() or some other mechanism?
> 
This is the number of queues from application point of view.
PMD can implement just one queue using locks.

Best,
Ori
> ::::