[dpdk-dev] [PATCH 3/5] eventdev: introduce specialized enqueue forward op variant

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

Introducing the rte_event_enqueue_new_burst() for enabling the
PMD, an optimization opportunity to optimize if all the events in
the enqueue burst has the op type of RTE_EVENT_OP_FORWARD.

If a PMD does not have any optimization opportunity
for this operation then the PMD can choose the generic enqueue
burst PMD callback as the fallback.

Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
---
This patch is based on the following dicussion on ml
http://dpdk.org/ml/archives/dev/2017-June/068859.html
---
 drivers/event/octeontx/ssovf_evdev.c |  1 +
 drivers/event/sw/sw_evdev.c          |  1 +
 lib/librte_eventdev/rte_eventdev.h   | 51 ++++++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+)

diff --git a/drivers/event/octeontx/ssovf_evdev.c b/drivers/event/octeontx/ssovf_evdev.c
index 0d0c6a186..5f97beeac 100644
--- a/drivers/event/octeontx/ssovf_evdev.c
+++ b/drivers/event/octeontx/ssovf_evdev.c
@@ -159,6 +159,7 @@ ssovf_fastpath_fns_set(struct rte_eventdev *dev)
 	dev->enqueue       = ssows_enq;
 	dev->enqueue_burst = ssows_enq_burst;
 	dev->enqueue_new_burst = ssows_enq_burst;
+	dev->enqueue_forward_burst = ssows_enq_burst;
 	dev->dequeue       = ssows_deq;
 	dev->dequeue_burst = ssows_deq_burst;
 
diff --git a/drivers/event/sw/sw_evdev.c b/drivers/event/sw/sw_evdev.c
index 951ad1b33..2b0b4fafa 100644
--- a/drivers/event/sw/sw_evdev.c
+++ b/drivers/event/sw/sw_evdev.c
@@ -797,6 +797,7 @@ sw_probe(struct rte_vdev_device *vdev)
 	dev->enqueue = sw_event_enqueue;
 	dev->enqueue_burst = sw_event_enqueue_burst;
 	dev->enqueue_new_burst = sw_event_enqueue_burst;
+	dev->enqueue_forward_burst = sw_event_enqueue_burst;
 	dev->dequeue = sw_event_dequeue;
 	dev->dequeue_burst = sw_event_dequeue_burst;
 	dev->schedule = sw_event_schedule;
diff --git a/lib/librte_eventdev/rte_eventdev.h b/lib/librte_eventdev/rte_eventdev.h
index 132f75fda..29d707f9d 100644
--- a/lib/librte_eventdev/rte_eventdev.h
+++ b/lib/librte_eventdev/rte_eventdev.h
@@ -1067,6 +1067,8 @@ struct rte_eventdev {
 	/**< Pointer to PMD enqueue burst function. */
 	event_enqueue_burst_t enqueue_new_burst;
 	/**< Pointer to PMD enqueue burst function(op new variant) */
+	event_enqueue_burst_t enqueue_forward_burst;
+	/**< Pointer to PMD enqueue burst function(op forward variant) */
 	event_dequeue_t dequeue;
 	/**< Pointer to PMD dequeue function. */
 	event_dequeue_burst_t dequeue_burst;
@@ -1232,6 +1234,55 @@ rte_event_enqueue_new_burst(uint8_t dev_id, uint8_t port_id,
 }
 
 /**
+ * Enqueue a burst of events objects of operation type *RTE_EVENT_OP_FORWARD*
+ * on an event device designated by its *dev_id* through the event port
+ * specified by *port_id*.
+ *
+ * Provides the same functionality as rte_event_enqueue_burst(), expect that
+ * application can use this API when the all objects in the burst contains
+ * the enqueue operation of the type *RTE_EVENT_OP_FORWARD*. This specialized
+ * function can provide the additional hint to the PMD and optimize if possible.
+ *
+ * The rte_event_enqueue_new_burst() result is undefined if the enqueue burst
+ * has event object of operation type != RTE_EVENT_OP_FORWARD.
+ *
+ * @param dev_id
+ *   The identifier of the device.
+ * @param port_id
+ *   The identifier of the event port.
+ * @param ev
+ *   Points to an array of *nb_events* objects of type *rte_event* structure
+ *   which contain the event object enqueue operations to be processed.
+ * @param nb_events
+ *   The number of event objects to enqueue, typically number of
+ *   rte_event_port_enqueue_depth() available for this port.
+ *
+ * @return
+ *   The number of event objects actually enqueued on the event device. The
+ *   return value can be less than the value of the *nb_events* parameter when
+ *   the event devices queue is full or if invalid parameters are specified in a
+ *   *rte_event*. If the return value is less than *nb_events*, the remaining
+ *   events at the end of ev[] are not consumed and the caller has to take care
+ *   of them, and rte_errno is set accordingly. Possible errno values include:
+ *   - -EINVAL  The port ID is invalid, device ID is invalid, an event's queue
+ *              ID is invalid, or an event's sched type doesn't match the
+ *              capabilities of the destination queue.
+ *   - -ENOSPC  The event port was backpressured and unable to enqueue
+ *              one or more events. This error code is only applicable to
+ *              closed systems.
+ * @see rte_event_port_enqueue_depth() rte_event_enqueue_burst()
+ */
+static inline uint16_t
+rte_event_enqueue_forward_burst(uint8_t dev_id, uint8_t port_id,
+			const struct rte_event ev[], uint16_t nb_events)
+{
+	const struct rte_eventdev *dev = &rte_eventdevs[dev_id];
+
+	return __rte_event_enqueue_burst(dev_id, port_id, ev, nb_events,
+			dev->enqueue_forward_burst);
+}
+
+/**
  * Converts nanoseconds to *timeout_ticks* value for rte_event_dequeue_burst()
  *
  * If the device is configured with RTE_EVENT_DEV_CFG_PER_DEQUEUE_TIMEOUT flag
-- 
2.13.2