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

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

On 6/17/2018 4:39 PM, Jerin Jacob wrote:

> -----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

Yes.
>> +/**
>> + * @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?

OK.
>> +/**
>> + * @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);
>> +
I think the queue_del() function  should have to take id.
>> +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?
I am fine with the suggestion.

Thanks for the review,
Nikhil