[dpdk-dev] [RFC] eventdev: add event adapter for ethernet Rx queues

[Gage Eads]

From: Nikhil Rao <nikhil.rao at intel.com>

Eventdev-based networking applications require a component to dequeue
packets from NIC Rx queues and inject them into eventdev queues[1]. While
some platforms (e.g. Cavium Octeontx) do this operation in hardware, other
platforms use software.

This RFC introduces an ethernet Rx event adapter and a proposed header
file. This adapter service dequeues packets from ethernet devices and
enqueues them to event devices.

The adapter is designed to work with the EAL service core proposal[2]. If
an application determines that the adapter is required, it can register and
launch it on a service core. Alternatively, this adapter can serve as a
template for applications to design customer ethernet Rx event adapters
better suited to their needs.

The adapter can service multiple ethernet devices and queues. Each queue is
configured with a servicing weight to control the relative frequency with
which the adapter polls the queue, and the event fields to use when
constructing packet events. The adapter has two modes for programming an
event's flow ID: use a static per-queue user-specified value or use the RSS
hash.

A detailed description of the adapter is contained in the header's
comments.

[1] http://dpdk.org/ml/archives/dev/2017-May/065341.html
[2] http://dpdk.org/ml/archives/dev/2017-May/065207.html

Signed-off-by: Nikhil Rao <nikhil.rao at intel.com>
Signed-off-by: Gage Eads <gage.eads at intel.com>
---
 lib/librte_eventdev/rte_eth_rx_event_adapter.h | 285 +++++++++++++++++++++++++
 lib/librte_eventdev/rte_eventdev_version.map   |  14 ++
 2 files changed, 299 insertions(+)
 create mode 100644 lib/librte_eventdev/rte_eth_rx_event_adapter.h

diff --git a/lib/librte_eventdev/rte_eth_rx_event_adapter.h b/lib/librte_eventdev/rte_eth_rx_event_adapter.h
new file mode 100644
index 0000000..b54927d
--- /dev/null
+++ b/lib/librte_eventdev/rte_eth_rx_event_adapter.h
@@ -0,0 +1,285 @@
+/*
+ *   Copyright(c) 2017 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_ETH_RX_EVENT_ADAPTER_
+#define _RTE_ETH_RX_EVENT_ADAPTER_
+
+/**
+ * @file
+ *
+ * RTE Ethernet Rx Adapter for Eventdev
+ *
+ * An eventdev-based packet processing application enqueues/dequeues mbufs
+ * to/from the event device. The ethernet Rx event adapter's role is to transfer
+ * mbufs from the ethernet receive queues managed by DPDK to an event device.
+ * The application uses the adapter APIs to configure the packet flow between
+ * the ethernet devices and event devices. The adapter is designed to work with
+ * the EAL service cores. The adapter's work can be parallelized by dividing the
+ * NIC Rx queues among multiple adapter services that run in parallel.
+ *
+ * Before using the adapter, the application needs to enumerate and configure
+ * the ethernet devices that it wishes to use. This is typically done using the
+ * following DPDK ethdev functions:
+ *  - rte_eth_dev_configure()
+ *  - rte_eth_tx_queue_setup()
+ *  - rte_eth_rx_queue_setup()
+ *  - rte_eth_dev_start()
+ *
+ * The application also configures an event device and creates event ports
+ * to interface with the event device. In addition to the event ports used by
+ * its packet processing functions, the application creates an event port
+ * to be used by this adapter.
+ *
+ * The ethernet Rx event adapter's functions are:
+ *  - rte_eth_rx_event_adapter_create()
+ *  - rte_eth_rx_event_adapter_free()
+ *  - rte_eth_rx_event_adapter_dev_add()
+ *  - rte_eth_rx_event_adapter_dev_del()
+ *  - rte_eth_rx_event_adapter_queue_add()
+ *  - rte_eth_rx_event_adapter_run()
+ *  - rte_eth_rx_event_adapter_stats_get()
+ *  - rte_eth_rx_event_adapter_stats_reset()
+ *
+ * The applicaton creates an event to ethernet adapter using
+ * rte_eth_rx_event_adapter_create(). The event device and event port
+ * identifiers are passed to this function. Next, the application adds ethernet
+ * devices to this adapter using rte_eth_rx_event_adapter_dev_add().
+ *
+ * The adapter needs to know which ethernet rx queues to poll for mbufs as well
+ * as event device parameters such as the event queue identifier, event
+ * priority and scheduling type that the adapter should use when constructing
+ * events. The rte_eth_rx_event_adapter_queue_add() function is provided for
+ * this purpose.
+ *
+ * At the time of adding an ethernet device receive queue, the application can
+ * also specify a static event flow id and set the
+ * RTE_ETH_RX_EVENT_ADAPTER_QUEUE_FLOW_ID_VALID bit of the rx_queue_flags
+ * member of the rte_eth_rx_event_adapter_queue_config structure. If the
+ * RTE_ETH_RX_EVENT_ADAPTER_QUEUE_FLOW_ID_VALID isn't set, the flow id is
+ * assigned the value of the RSS hash. The adapter generates the RSS hash if it
+ * hasn't been already computed by the NIC, based on source and destination
+ * IPv4/6 addresses, using the rte_softrss_be() routine included in the DPDK.
+ *
+ * The servicing weight parameter in the rte_eth_rx_event_adapter_queue_config
+ * intended to provide application control of the polling frequency of ethernet
+ * device receive queues, for example, the application may want to poll higher
+ * priority queues with a higher frequency but at the same time not starve
+ * lower priority queues completely. If this parameter is zero and the receive
+ * interrupt is enabled when configuring the device, the receive queue is
+ * interrupt driven; else, the queue is assigned a servicing weight of one.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <rte_mbuf.h>
+#include <rte_eventdev.h>
+
+/* struct rte_eth_rx_event_adapter_queue_config flags definitions */
+#define RTE_ETH_RX_EVENT_ADAPTER_QUEUE_FLOW_ID_VALID	0x1
+/*< This flag indicates the flow identifier is valid */
+
+struct rte_eth_rx_event_adapter_config {
+	uint8_t event_dev_id;
+	/**< Event device identifier */
+	uint8_t rx_event_port_id;
+	/**< Event port identifier, the adapter enqueues mbuf events to this
+	 * port
+	 */
+};
+
+struct rte_eth_rx_event_adapter_queue_config {
+	uint32_t rx_queue_flags;
+	 /**< Flags for handling received packets */
+	uint16_t servicing_weight;
+	/**< Relative polling frequency of ethernet receive queue, if this
+	 * is set to zero, the Rx queue is interrupt driven
+	 */
+	struct rte_event ev;
+	/**<
+	 *  The values from the following event fields will be used when
+	 *  enqueuing mbuf events:
+	 *   - event_queue_id: Targeted event queue ID for received packets.
+	 *   - event_priority: Event priority of packets from this Rx queue in
+	 *                     the event queue relative to other events.
+	 *   - sched_type: Scheduling type for packets from this Rx queue.
+	 *   - flow_id: If the RTE_ETH_RX_EVENT_ADAPTER_QUEUE_FLOW_ID_VALID bit
+	 *		is set in rx_queue_flags, this flow_id is used for all
+	 *		packets received from this queue. Otherwise the flow ID
+	 *		is set to the RSS hash.
+	 */
+};
+
+struct rte_eth_rx_event_adapter_run_args {
+	uint8_t id;
+	/**< Adapter identifier */
+	unsigned int max_nb_rx;
+	/**< The adapter can return early if it has processed at least
+	 * max_nb_rx mbufs. This isn't treated as a requirement; batching may
+	 * cause the adapter to process more than max_nb_rx mbufs.
+	 */
+};
+
+struct rte_eth_rx_event_adapter_stats {
+	uint64_t rx_poll_count;
+	/**< Receive queue poll count across both polled and interrupt mode
+	 * queues
+	 */
+	uint64_t rx_packets;
+	/**< Received packet count */
+	uint64_t rx_enq_fail;
+	/**< Eventdev enqueue failed count */
+	uint64_t rx_enq_retry;
+	/**< Eventdev enqueue retry count */
+};
+
+/**
+ * Create a new ethernet Rx event adapter with the specified identifier.
+ *
+ * @param adapter_id
+ *   Event adapter identifier.
+ * @param config
+ *   Event adapter config parameters.
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure
+ */
+int rte_eth_rx_event_adapter_create(
+	uint8_t id,
+	const struct rte_eth_rx_event_adapter_config *config);
+
+/**
+ * Free an event adapter
+ *
+ * @param id
+ *   Adapter identifier.
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure
+ */
+int rte_eth_rx_event_adapter_free(uint8_t id);
+
+/**
+ * Add eth device to the event adapter
+ *
+ * @param id
+ *   Adapter identifier.
+ * @param eth_dev_id
+ *  Port identifier of the Ethernet device.
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure
+ */
+int rte_eth_rx_event_adapter_dev_add(uint8_t id, uint8_t eth_dev_id);
+
+/**
+ * Delete eth device from an event adapter
+ *
+ * @param id
+ *   Adapter identifier.
+ * @param eth_dev_id
+ *  Port identifier of the Ethernet device.
+ * @return
+ *   - 0: Success
+ *   - <0: Error code on failure
+ */
+int rte_eth_rx_event_adapter_dev_del(uint8_t id, uint8_t eth_dev_id);
+
+/**
+ * Add receive queue to event adapter
+ *
+ * @param id
+ *   Adapter identifier.
+ * @param eth_dev_id
+ *  Port identifier of Ethernet device.
+ * @param rx_queue_id
+ *  Ethernet device receive queue index.
+ * @param config
+ *  Additonal configuration structure.
+ * @return
+ *  - 0: Success, Receive queue added correctly.
+ *  - <0: Error code on failure.
+ */
+int rte_eth_event_rx_queue_add(
+	uint8_t id,
+	uint8_t eth_dev_id,
+	uint16_t rx_queue_id,
+	const struct rte_eth_rx_event_adapter_queue_config *config);
+
+/**
+ * Service core run function. The receive function dequeues mbufs from the
+ * ethernet device receive queues associated with the adapter and enqueues
+ * mbuf events to the adapter's receive event port.
+ *
+ * @param args
+ *  A pointer to a struct rte_eth_rx_event_adapter_run_args. This is a void*
+ *  to match the service core run function prototype.
+ * @return
+ *  - 0: Success.
+ *  - <0: Error code on failure.
+ */
+int rte_eth_rx_event_adapter_run(void *args);
+
+
+/**
+ * Retrieve statistics for an adapter
+ *
+ * @param id
+ *   Adapter identifier.
+ * @param stats
+ *  A pointer to structure used to retrieve statistics for an adapter.
+ * @return
+ *  - 0: Success, retrieved successfully.
+ *  - <0: Error code on failure.
+ */
+int rte_eth_rx_event_adapter_stats_get(uint8_t id,
+			       struct rte_eth_rx_event_adapter_stats *stats);
+
+
+/**
+ * Reset statistics for an adapter
+ *
+ * @param id
+ *   Adapter identifier.
+ * @return
+ *  - 0: Success, statistics reset successfully.
+ *  - <0: Error code on failure.
+ */
+int rte_eth_rx_event_adapter_stats_reset(uint8_t id);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_ETH_RX_EVENT_ADAPTER_ */
diff --git a/lib/librte_eventdev/rte_eventdev_version.map b/lib/librte_eventdev/rte_eventdev_version.map
index 1fa6b33..8dfc611 100644
--- a/lib/librte_eventdev/rte_eventdev_version.map
+++ b/lib/librte_eventdev/rte_eventdev_version.map
@@ -42,3 +42,17 @@ DPDK_17.05 {
 
 	local: *;
 };
+
+DPDK_17.08 {
+	global:
+
+	rte_eth_rx_event_adapter_create;
+	rte_eth_rx_event_adapter_free;
+	rte_eth_rx_event_adapter_dev_add;
+	rte_eth_rx_event_adapter_dev_del;
+	rte_eth_rx_event_adapter_queue_add;
+	rte_eth_rx_event_adapter_run;
+	rte_eth_rx_event_adapter_stats_get;
+	rte_eth_rx_event_adapter_stats_reset;
+
+} DPDK_17.05;
-- 
2.7.4