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

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

-----Original Message-----
> Date: Wed, 24 May 2017 10:00:22 +0530
> From: "Rao, Nikhil" <nikhil.rao@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, Gage Eads
>  <gage.eads@intel.com>
> CC: dev@dpdk.org, thomas@monjalon.net, bruce.richardson@intel.com,
>  harry.van.haaren@intel.com, hemant.agrawal@nxp.com, nipun.gupta@nxp.com,
>  narender.vangati@intel.com, nikhil.rao@intel.com
> Subject: Re: [RFC] eventdev: add event adapter for ethernet Rx queues
> User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101
>  Thunderbird/38.7.2
> 
> Hi Jerin,

Hi Nikhil,

> 
> Comments inline.
> 
> Also, another function needed is
> bool rte_event_eth_rx_adapter_multithread_capable(void). 
> 
> This would be used to set the "multithread_capable" service core 
> configuration parameter. 

OK.

I was thinking like, in order to effectively use adapter scheme, it should
use ops scheme like rte_flow or rte_tm[1] where the same API can be
can be used for both HW and SW. If we see, Both RFC[2], We have a lot of
similarities. I think, We can base the eth_rx_adapter model based on your SW
requirement RFC and introduce capability wherever it is not applicable for HW or
vice versa.

See below as a example[3]. Can you take of the same in v1 of this
series? if you don't have the bandwidth then I can try. Let me know.
Thoughts?

[1]
http://dpdk.org/dev/patchwork/patch/25275/
http://dpdk.org/dev/patchwork/patch/25276/

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


/* adapter has inbuilt port, no need to create producer port */
#define RTE_EVENT_ETHDEV_CAP_INBUILT_PORT  (1ULL << 0)
/* adapter does not need service function */
#define RTE_EVENT_ETHDEV_CAP_NO_SERVICE_FUNC (1ULL << 1)

struct rte_event_eth_rx_adap_info {
	char name[32];
        uint32_t adapter_cap;
        /**< Ethdev RX adapter capabilities(RTE_EVENT_ETHDEV_CAP_)*/
}


struct rte_event_eth_rx_adap_cfg {
	uint8_t rx_event_port_id;
       /**< Event port identifier, the adapter enqueues mbuf events to this
        * port, Ignored when RTE_EVENT_ETHDEV_CAP_INBUILT_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
        * Ignored if RTE_EVENT_ETHDEV_CAP_NO_SERVICE_FUNC set
        */
       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.
        */
};

int rte_event_eth_rx_adapter_create(uint8_t id, uint8_t dev_id, uint8_t eth_port_id);
int rte_event_eth_rx_adapter_get_info(uint8_t id, struct rte_event_eth_rx_adap_info *info);
int rte_event_eth_rx_adapter_configure(uint8_t id, struct rte_event_eth_rx_adap_config *cfg);
int rte_event_eth_rx_adapter_queue_add(uint8_t id, int32_t rx_queue_id, const struct rte_eth_rx_event_adapter_queue_config *config);
int rte_event_eth_rx_adapter_queue_del(uint8_t id, int32_t rx_queue_id)
int rte_event_eth_rx_adapter_run();
int rte_event_eth_rx_adapter_free(uint8_t id);



> 
> Thanks,
> Nikhil
> 
> On 5/11/2017 10:08 PM, Jerin Jacob wrote:
> > -----Original Message-----
> >> Date: Tue, 9 May 2017 15:38:46 -0500
> >> From: Gage Eads <gage.eads@intel.com>
> >> To: dev@dpdk.org
> >> CC: nikhil.rao@intel.com, jerin.jacob@caviumnetworks.com,
> >>  thomas@monjalon.net, bruce.richardson@intel.com,
> >>  harry.van.haaren@intel.com, hemant.agrawal@nxp.com, nipun.gupta@nxp.com,
> >>  narender.vangati@intel.com
> >> Subject: [RFC] eventdev: add event adapter for ethernet Rx queues
> >> X-Mailer: git-send-email 2.7.4
> >>
> >> From: Nikhil Rao <nikhil.rao@intel.com>
> > 
> > Hi Nikhil and Gage,
> > 
> > Thanks for the RFC. A few questions and comments below.
> > Looks like SW has more constraints on event producer side, after we
> > finalize on this RFC(I guess only a few minor changes are only required).
> > I will align other[1] RFC based on _your_ RFC as we need to
> > converge on name space and we can't duplicate configs like struct
> > rte_event_dev_producer_conf etc
> > 
> > [1]
> > http://dpdk.org/ml/archives/dev/2017-May/065341.html
> > 
> >
> > 
> >> + */
> >> +
> >> +#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 {
> > 
> > Since this code is going to be at lib/librte_eventdev, We must start all
> > public symbols and file name with rte_event_*.
> > 
> > example:
> > May be this structure can be changed as rte_event_eth_rx_adapter_config
> 
> OK.
> 
> > 
> > 
> >> +	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 */
> > 
> > Better to add references with @see
> > example:
> > 	@see RTE_ETH_RX_EVENT_ADAPTER_QUEUE_FLOW_ID_VALID
> 
> OK.
> 
> > 
> >> +	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.
> > 
> > This scheme is good. I was duplicating the elements in "struct
> > rte_event_dev_producer_conf"
> > 
> > IMO, We need to set ev.event_type == RTE_EVENT_TYPE_ETHDEV implicitly in
> > library.
> > You can mention that here as a info.
> OK.
> 
> > 
> >> +	 */
> >> +};
> >> +
> >> +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);
> >> +
> > 
> > One adapter creates one service function. right?
> > It is good to mention the mapping.It is missing in the doc.
> 
> Yes, in this case, the application creates a service per adapter, it may create multiple
> Rx event adapters with each adapter handling a subset of Rx queues. As per Harry's
> patch, only DPDK internal components are expected to request service cores, once Harry posts
> an updated patch, I will make any necesssary changes and post the next version of this
> patch.
> 
> >> +/**
> >> + * 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);
> > 
> > rte_eth_event_rx_queue_add() also have eth_dev_id.What is the
> > significance of eth_dev_id here. Looks like eth_dev_id is a duplicate info.
> > 
> > if it is duplicate or it can be avoided then I propose to reduce the number
> > of APIs for easiness of application programming(i.e removing rte_eth_rx_event_adapter_dev_add,
> > rte_eth_rx_event_adapter_dev_del)
> OK.
> 
> > 
> > You can also mention the following for better clarify. If following is
> > true.If not, What do you think about, co-existence of poll and event mode?
> 
> Yes, its true.
> 
> > The rte_eth_rx_burst() result is undefined if application invokes on
> > bounded ethdev_port and rx_queue_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,
> > 
> > How about changing it as int32_t rx_queue_id and -1 to denote all Rx
> > queues configured for given eth_dev_id are added. This will avoid the
> > case where application needs to call this API one by one when application
> > interested in all the queues.
> 
> Sounds good.
>  
> >> +	const struct rte_eth_rx_event_adapter_queue_config *config);
> >> +
> > 
> > Don't we need rte_eth_event_rx_queue_del() for tear down?
> > 
> Yes.