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

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

-----Original Message-----
> Date: Wed, 13 Jun 2018 03:02:43 +0530
> From: Nikhil Rao <nikhil.rao@intel.com>
> To: jerin.jacob@caviumnetworks.com, olivier.matz@6wind.com
> CC: hemant.agrawal@nxp.com, dev@dpdk.org, narender.vangati@intel.com,
>  abhinandan.gujjar@intel.com, gage.eads@intel.com, jia.guo@intel.com,
>  cristian.dumitrescu@intel.com, Nikhil Rao <nikhil.rao@intel.com>
> Subject: [RFC v2] eventdev: event tx adapter APIs
> X-Mailer: git-send-email 1.8.3.1
> 
> 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.
> 

Overall it looks good. Some comments inline. I think you can change it
from RFC and send the implementation.

>  lib/librte_eventdev/rte_event_eth_tx_adapter.h | 380 +++++++++++++++++++++++++
>  lib/librte_eventdev/rte_eventdev.h             |   7 +-
>  lib/librte_mbuf/rte_mbuf.h                     |  20 +-

Please split mbuf changes in a separate patch.


>  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.

2018

> + */
> +
> +#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

s/transmit stage/ethernet transmit stage/

> + * 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

s/deqeueues/dequeues

> + * 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

s/adaptervia/adapter via

> + * 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
> + */

__rte_experimental missing in all the functions.

> +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);
> +


# Missing the rte_event_eth_tx_adapter_create_ext() prototype?

#I assume you will have rte_event_eth_tx_adapter_caps_get() with the
RTE_EVENT_ETH_TX_ADAPTER_CAP_INTERNAL_PORT capability

> +/**
> + * @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);
> +

How about changing to to rte_event_eth_tx_adapter_queue_add to inline
with Rx adapter?

> +/**
> + * @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
> +	 */

I think, we don't need the 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.

See rte_event_eth_tx_adapter_enqueue()

> +	 */
>  	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 */

s/overlaps/Overlaps/

> +			uint16_t resvd2;
> +			uint16_t txq_id;

/* The event eth Tx adapter transmit queue. See rte_event_eth_tx_adapter_enqueue() */

> +		};
>  		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)

Should we change to rte_pktmbuf_tx_adapter_txq to make it explicit that
it is related to Tx adapter?

> +
> +/**
>   * Prepend len bytes to an mbuf data area.
>   *
>   * Returns a pointer to the new
> -- 
> 1.8.3.1
>