[dpdk-dev] [RFC v2] eventdev: event tx adapter APIs

[Nikhil Rao <nikhil.rao@intel.com>]

Add common APIs for the transmit stage of an event driven
DPDK application. Also add a transmit queue field to the mbuf
that is used by the adapter to transmit mbufs.

Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
---

Changelog
=========

v1->v2:
 * Add the tx_adapter_enqueue function to struct rte_eventdev.
   It is set to the common Tx adapter function when creating the adapter
   if the eventdev PMD does not support it or if the
   DEV_TX_OFFLOAD_MT_LOCKFREE flag is NOT set on all ethernet devices.
 * Add the rte_event_eth_tx_adapter_enqueue() API.
 * Add the txq_id field to struct rte_mbuf.

 lib/librte_eventdev/rte_event_eth_tx_adapter.h | 380 +++++++++++++++++++++++++
 lib/librte_eventdev/rte_eventdev.h             |   7 +-
 lib/librte_mbuf/rte_mbuf.h                     |  20 +-
 3 files changed, 405 insertions(+), 2 deletions(-)
 create mode 100644 lib/librte_eventdev/rte_event_eth_tx_adapter.h

diff --git a/lib/librte_eventdev/rte_event_eth_tx_adapter.h b/lib/librte_eventdev/rte_event_eth_tx_adapter.h
new file mode 100644
index 0000000..a0e8505
--- /dev/null
+++ b/lib/librte_eventdev/rte_event_eth_tx_adapter.h
@@ -0,0 +1,380 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2017 Intel Corporation.
+ */
+
+#ifndef _RTE_EVENT_ETH_TX_ADAPTER_
+#define _RTE_EVENT_ETH_TX_ADAPTER_
+
+/**
+ * @file
+ *
+ * RTE Event Ethernet Tx Adapter
+ *
+ * The event ethernet Tx adapter provides configuration and data path APIs
+ * for the transmit stage of an event driven packet processing application.
+ * These APIs abstract the implementation of the transmit stage and allow the
+ * the application to use eventdev PMD support or a common implementation.
+ *
+ * In the common implementation, the application uses the adapter API to
+ * enqueue mbufs to the adapter which runs as a rte_service function. The
+ * service function deqeueues events from its event port and transmits the
+ * mbufs referenced by these events.
+ *
+ * The ethernet Tx event adapter APIs are:
+ *
+ *  - rte_event_eth_tx_adapter_create()
+ *  - rte_event_eth_tx_adapter_create_ext()
+ *  - rte_event_eth_tx_adapter_free()
+ *  - rte_event_eth_tx_adapter_start()
+ *  - rte_event_eth_tx_adapter_stop()
+ *  - rte_event_eth_tx_adapter_queue_start()
+ *  - rte_event_eth_tx_adapter_queue_stop()
+ *  - rte_event_eth_tx_adapter_enqueue()
+ *  - rte_event_eth_tx_adapter_stats_get()
+ *  - rte_event_eth_tx_adapter_stats_reset()
+ *
+ * The application creates the adapter using
+ * rte_event_eth_tx_adapter_create(). The adapter may internally create an event
+ * port using the port configuration parameter.
+ * The adapter is responsible for linking the queue as per its implementation,
+ * for example in the case of the service function, the adapter links this queue
+ * to the event port it will dequeue events from.
+ *
+ * The application uses rte_event_eth_tx_adapter_enqueue() to send mbufs to the
+ * adaptervia this event queue. The ethernet port and transmit queue index to
+ * transmit the mbuf on are specified in the mbuf.
+ *
+ * The application can start and stop the adapter using the
+ * rte_event_eth_tx_adapter_start/stop() calls.
+ *
+ * To support dynamic reconfiguration of Tx queues, the application can
+ * call rte_event_eth_tx_adapter_queue_start()/stop() to synchronize
+ * access to the Tx queue with the adapter. For example, if the application
+ * wants to reconfigure a Tx queue that could be concurrently
+ * being accessed by the adapter, it calls rte_event_eth_tx_adapter_queue_stop()
+ * first, reconfigures the queue and then calls
+ * rte_event_eth_tx_adapter_queue_start() which signals to the adapter
+ * that it is safe to resume access to the Tx queue.
+ *
+ * The common adapter implementation uses an EAL service function as described
+ * before and its execution is controlled using the rte_service APIs. The
+ * rte_event_eth_tx_adapter_service_id_get()
+ * function can be used to retrieve the adapter's service function ID.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+#include "rte_eventdev.h"
+
+#define RTE_EVENT_ETH_TX_ADAPTER_MAX_INSTANCE 32
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Adapter configuration structure
+ */
+struct rte_event_eth_tx_adapter_conf {
+	uint8_t event_port_id;
+	/**< Event port identifier, the adapter service function dequeues mbuf
+	 * events from this port.
+	 */
+	uint32_t max_nb_tx;
+	/**< The adapter can return early if it has processed at least
+	 * max_nb_tx mbufs. This isn't treated as a requirement; batching may
+	 * cause the adapter to process more than max_nb_tx mbufs.
+	 */
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Function type used for adapter configuration callback. The callback is
+ * used to fill in members of the struct rte_event_eth_tx_adapter_conf, this
+ * callback is invoked when creating a SW service to transmit packets.
+ *
+ * @param id
+ *  Adapter identifier.
+ * @param dev_id
+ *  Event device identifier.
+ * @param [out] conf
+ *  Structure that needs to be populated by this callback.
+ * @param arg
+ *  Argument to the callback. This is the same as the conf_arg passed to the
+ *  rte_event_eth_tx_adapter_create_ext().
+ *
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure
+ */
+typedef int (*rte_event_eth_tx_adapter_conf_cb) (uint8_t id, uint8_t dev_id,
+			struct rte_event_eth_tx_adapter_conf *conf,
+			void *arg);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * A structure used to retrieve statistics for an eth tx adapter instance.
+ */
+struct rte_event_eth_tx_adapter_stats {
+	uint64_t event_poll_count;
+	/*< Event port poll count */
+	uint64_t tx_packets;
+	/*< Number of packets transmitted */
+	uint64_t tx_dropped;
+	/*< Number of packets dropped */
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Create a new event ethernet Tx adapter with the specified identifier.
+ *
+ * @param id
+ *  The identifier of the event ethernet Tx adapter.
+ * @param dev_id
+ *  The event device identifier.
+ * @param queue_id
+ *  The event queue identifier.
+ * @param port_config
+ *  Event port configuration, the adapter uses this configuration to
+ *  create an event port if needed. It uses this port to dequeue
+ *  events that are sent to it by rte_event_eth_tx_adapter_enqueue()
+ *
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure
+ */
+int rte_event_eth_tx_adapter_create(uint8_t id, uint8_t dev_id,
+				uint8_t queue_id,
+				struct rte_event_port_conf *port_config);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Free an event adapter
+ *
+ * @param id
+ *  Adapter identifier.
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure, If the adapter still has Tx queues
+ *      added to it, the function returns -EBUSY.
+ */
+int rte_event_eth_tx_adapter_free(uint8_t id);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Start ethernet Tx event adapter
+ *
+ * @param id
+ *  Adapter identifier.
+ * @return
+ *  - 0: Success, Adapter started correctly.
+ *  - <0: Error code on failure.
+ */
+int rte_event_eth_tx_adapter_start(uint8_t id);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Stop ethernet Tx event adapter
+ *
+ * @param id
+ *  Adapter identifier.
+ * @return
+ *  - 0: Success, Adapter started correctly.
+ *  - <0: Error code on failure.
+ */
+int rte_event_eth_tx_adapter_stop(uint8_t id);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Signal the Tx adapter to start processing mbufs for a
+ * Tx queue. A queue value of -1 is used to indicate all
+ * queues within the device.
+ *
+ * @param id
+ *  Adapter identifier.
+ * @param eth_dev_id
+ *  Ethernet Port Identifier.
+ * @param queue
+ *  Tx queue index.
+ *
+ * @return
+ *  - 0: Success, Adapter started correctly.
+ *  - <0: Error code on failure.
+ */
+int rte_event_eth_tx_adapter_queue_start(uint8_t id,
+					uint16_t eth_dev_id,
+					int32_t queue);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Signal the Tx adapter to stop processing mbufs for a
+ * Tx queue. A queue value of -1 is used to indicate all
+ * queues within the device.
+ *
+ * @param id
+ *  Adapter identifier.
+ * @param eth_dev_id
+ *  Ethernet Port Identifier.
+ * @param queue
+ *  Tx queue index.
+ *
+ * @return
+ *  - 0: Success, Adapter started correctly.
+ *  - <0: Error code on failure.
+ */
+int rte_event_eth_tx_adapter_queue_stop(uint8_t id,
+					uint16_t eth_dev_id,
+					int32_t queue);
+
+static __rte_always_inline uint16_t
+__rte_event_eth_tx_adapter_enqueue(uint8_t id, uint8_t dev_id, uint8_t port_id,
+				const struct rte_event ev[],
+				uint16_t nb_events,
+				const event_tx_adapter_enqueue fn)
+{
+	const struct rte_eventdev *dev = &rte_eventdevs[dev_id];
+
+#ifdef RTE_LIBRTE_EVENTDEV_DEBUG
+	if (id >= RTE_EVENT_ETH_TX_ADAPTER_MAX_INSTANCE || 
+		dev_id >= RTE_EVENT_MAX_DEVS ||
+		!rte_eventdevs[dev_id].attached) {
+		rte_errno = -EINVAL;
+		return 0;
+	}
+
+	if (port_id >= dev->data->nb_ports) {
+		rte_errno = -EINVAL;
+		return 0;
+	}
+#endif
+	/*
+	 * TODO: Do we need a special case for nb_events == 1
+	 */
+	return fn(id, dev, dev->data->ports[port_id], ev, nb_events);
+}
+
+/**
+ * Enqueue a burst of events objects or an event object supplied in *rte_event*
+ * structure on an  event device designated by its *dev_id* through the event
+ * port specified by *port_id*. The the event queue on which it will be enqueued
+ * id derived from the adapter id parameter.
+ *
+ * The *nb_events* parameter is the number of event objects to enqueue which are
+ * supplied in the *ev* array of *rte_event* structure.
+ *
+ * The rte_event_eth_tx_adapter_enqueue() function returns the number of
+ * events objects it actually enqueued. A return value equal to *nb_events*
+ * means that all event objects have been enqueued.
+ *
+ * @param id
+ *  The identifier of the tx adapter.
+ * @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.
+ */
+static inline uint16_t
+rte_event_eth_tx_adapter_enqueue(uint8_t id, 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_eth_tx_adapter_enqueue(id, dev_id, port_id, ev,
+						nb_events,
+						dev->tx_adapter_enqueue);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Retrieve statistics for an adapter
+ *
+ * @param id
+ *  Adapter identifier.
+ * @param [out] stats
+ *  A pointer to structure used to retrieve statistics for an adapter.
+ * @return
+ *  - 0: Success, retrieved successfully.
+ *  - <0: Error code on failure.
+ */
+int rte_event_eth_tx_adapter_stats_get(uint8_t id,
+				struct rte_event_eth_tx_adapter_stats *stats);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Reset statistics for an adapter.
+ *
+ * @param id
+ *  Adapter identifier.
+ * @return
+ *  - 0: Success, statistics reset successfully.
+ *  - <0: Error code on failure.
+ */
+int rte_event_eth_tx_adapter_stats_reset(uint8_t id);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Retrieve the service ID of an adapter. If the adapter doesn't use
+ * a rte_service function, this function returns -ESRCH.
+ *
+ * @param id
+ *  Adapter identifier.
+ * @param [out] service_id
+ *  A pointer to a uint32_t, to be filled in with the service id.
+ * @return
+ *  - 0: Success
+ *  - <0: Error code on failure, if the adapter doesn't use a rte_service
+ * function, this function returns -ESRCH.
+ */
+int rte_event_eth_tx_adapter_service_id_get(uint8_t id, uint32_t *service_id);
+
+#ifdef __cplusplus
+}
+#endif
+#endif	/* _RTE_EVENT_ETH_TX_ADAPTER_ */
diff --git a/lib/librte_eventdev/rte_eventdev.h b/lib/librte_eventdev/rte_eventdev.h
index b6fd6ee..1bf28a0 100644
--- a/lib/librte_eventdev/rte_eventdev.h
+++ b/lib/librte_eventdev/rte_eventdev.h
@@ -1203,6 +1203,10 @@ typedef uint16_t (*event_dequeue_t)(void *port, struct rte_event *ev,
 typedef uint16_t (*event_dequeue_burst_t)(void *port, struct rte_event ev[],
 		uint16_t nb_events, uint64_t timeout_ticks);
 /**< @internal Dequeue burst of events from port of a device */
+typedef uint16_t (*event_tx_adapter_enqueue)(uint8_t id,
+			const struct rte_eventdev *dev, void *port,
+			const struct rte_event ev[], uint16_t nb_events);
+/**< @internal Enqueue burst of events on port of a device */
 
 #define RTE_EVENTDEV_NAME_MAX_LEN	(64)
 /**< @internal Max length of name of event PMD */
@@ -1266,7 +1270,8 @@ struct rte_eventdev {
 	/**< Pointer to PMD dequeue function. */
 	event_dequeue_burst_t dequeue_burst;
 	/**< Pointer to PMD dequeue burst function. */
-
+	event_tx_adapter_enqueue tx_adapter_enqueue;
+	/**< Pointer to PMD tx adapter enqueue function. */
 	struct rte_eventdev_data *data;
 	/**< Pointer to device data */
 	struct rte_eventdev_ops *dev_ops;
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 4fd9a0d..c59389c 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -464,7 +464,9 @@ struct rte_mbuf {
 	};
 	uint16_t nb_segs;         /**< Number of segments. */
 
-	/** Input port (16 bits to support more than 256 virtual ports). */
+	/** Input port (16 bits to support more than 256 virtual ports).
+	 * The event eth Tx adapter uses this field to specify the output port.
+	 */
 	uint16_t port;
 
 	uint64_t ol_flags;        /**< Offload features. */
@@ -511,6 +513,7 @@ struct rte_mbuf {
 	/** VLAN TCI (CPU order), valid if PKT_RX_VLAN is set. */
 	uint16_t vlan_tci;
 
+	RTE_STD_C11
 	union {
 		uint32_t rss;     /**< RSS hash result if RSS enabled */
 		struct {
@@ -531,6 +534,11 @@ struct rte_mbuf {
 			uint32_t lo;
 			uint32_t hi;
 		} sched;          /**< Hierarchical scheduler */
+		struct {
+			uint32_t resvd1; /* overlaps with rte_sched_port_hierarchy::color */
+			uint16_t resvd2;
+			uint16_t txq_id;
+		};
 		uint32_t usr;	  /**< User defined tags. See rte_distributor_process() */
 	} hash;                   /**< hash information */
 
@@ -1880,6 +1888,16 @@ static inline struct rte_mbuf *rte_pktmbuf_lastseg(struct rte_mbuf *m)
 #define rte_pktmbuf_data_len(m) ((m)->data_len)
 
 /**
+ * A macro that returns the txq field of the mbuf
+ *
+ * The value can be read or assigned.
+ *
+ * @param m
+ *   The packet mbuf.
+ */
+#define rte_pktmbuf_tx_queue(m) ((m)->txq_id)
+
+/**
  * Prepend len bytes to an mbuf data area.
  *
  * Returns a pointer to the new
-- 
1.8.3.1