Re: [dpdk-dev] [PATCH v5 4/8] eventdev: add Rx adapter event vector support

[Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>]

>-----Original Message-----
>From: Jayatheerthan, Jay <jay.jayatheerthan@intel.com>
>Sent: Thursday, March 25, 2021 4:07 PM
>To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin
>Jacob Kollanukkaran <jerinj@marvell.com>; Carrillo, Erik G
><erik.g.carrillo@intel.com>; Gujjar, Abhinandan S
><abhinandan.gujjar@intel.com>; McDaniel, Timothy
><timothy.mcdaniel@intel.com>; hemant.agrawal@nxp.com; Van
>Haaren, Harry <harry.van.haaren@intel.com>; mattias.ronnblom
><mattias.ronnblom@ericsson.com>; Ma, Liang J
><liang.j.ma@intel.com>
>Cc: dev@dpdk.org
>Subject: [EXT] RE: [dpdk-dev] [PATCH v5 4/8] eventdev: add Rx adapter
>event vector support
>
>External Email
>
>----------------------------------------------------------------------
>> -----Original Message-----
>> From: pbhagavatula@marvell.com <pbhagavatula@marvell.com>
>> Sent: Wednesday, March 24, 2021 10:35 AM
>> To: jerinj@marvell.com; Jayatheerthan, Jay
><jay.jayatheerthan@intel.com>; Carrillo, Erik G
><erik.g.carrillo@intel.com>; Gujjar,
>> Abhinandan S <abhinandan.gujjar@intel.com>; McDaniel, Timothy
><timothy.mcdaniel@intel.com>; hemant.agrawal@nxp.com; Van
>> Haaren, Harry <harry.van.haaren@intel.com>; mattias.ronnblom
><mattias.ronnblom@ericsson.com>; Ma, Liang J
>> <liang.j.ma@intel.com>
>> Cc: dev@dpdk.org; Pavan Nikhilesh <pbhagavatula@marvell.com>
>> Subject: [dpdk-dev] [PATCH v5 4/8] eventdev: add Rx adapter event
>vector support
>>
>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>
>> Add event vector support for event eth Rx adapter, the
>implementation
>> creates vector flows based on port and queue identifier of the
>received
>> mbufs.
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>> ---
>>  lib/librte_eventdev/eventdev_pmd.h            |   7 +-
>>  .../rte_event_eth_rx_adapter.c                | 257 ++++++++++++++++--
>>  lib/librte_eventdev/rte_eventdev.c            |   6 +-
>>  3 files changed, 250 insertions(+), 20 deletions(-)
>>
>> diff --git a/lib/librte_eventdev/eventdev_pmd.h
>b/lib/librte_eventdev/eventdev_pmd.h
>> index 9297f1433..0f724ac85 100644
>> --- a/lib/librte_eventdev/eventdev_pmd.h
>> +++ b/lib/librte_eventdev/eventdev_pmd.h
>> @@ -69,9 +69,10 @@ extern "C" {
>>  	} \
>>  } while (0)
>>
>> -#define RTE_EVENT_ETH_RX_ADAPTER_SW_CAP \
>> -
>	((RTE_EVENT_ETH_RX_ADAPTER_CAP_OVERRIDE_FLOW_ID) |
>\
>> -
>	(RTE_EVENT_ETH_RX_ADAPTER_CAP_MULTI_EVENTQ))
>> +#define RTE_EVENT_ETH_RX_ADAPTER_SW_CAP
>\
>> +	((RTE_EVENT_ETH_RX_ADAPTER_CAP_OVERRIDE_FLOW_ID) |
>\
>> +	 (RTE_EVENT_ETH_RX_ADAPTER_CAP_MULTI_EVENTQ) |
>\
>> +	 (RTE_EVENT_ETH_RX_ADAPTER_CAP_EVENT_VECTOR))
>>
>>  #define RTE_EVENT_CRYPTO_ADAPTER_SW_CAP \
>>
>	RTE_EVENT_CRYPTO_ADAPTER_CAP_SESSION_PRIVATE_DATA
>> diff --git a/lib/librte_eventdev/rte_event_eth_rx_adapter.c
>b/lib/librte_eventdev/rte_event_eth_rx_adapter.c
>> index ac8ba5bf0..c71990078 100644
>> --- a/lib/librte_eventdev/rte_event_eth_rx_adapter.c
>> +++ b/lib/librte_eventdev/rte_event_eth_rx_adapter.c
>> @@ -26,6 +26,10 @@
>>  #define BATCH_SIZE		32
>>  #define BLOCK_CNT_THRESHOLD	10
>>  #define ETH_EVENT_BUFFER_SIZE	(4*BATCH_SIZE)
>> +#define MAX_VECTOR_SIZE		1024
>> +#define MIN_VECTOR_SIZE		4
>> +#define MAX_VECTOR_NS		1E9
>> +#define MIN_VECTOR_NS		1E5
>>
>>  #define ETH_RX_ADAPTER_SERVICE_NAME_LEN	32
>>  #define ETH_RX_ADAPTER_MEM_NAME_LEN	32
>> @@ -59,6 +63,20 @@ struct eth_rx_poll_entry {
>>  	uint16_t eth_rx_qid;
>>  };
>>
>> +struct eth_rx_vector_data {
>> +	TAILQ_ENTRY(eth_rx_vector_data) next;
>> +	uint16_t port;
>> +	uint16_t queue;
>> +	uint16_t max_vector_count;
>> +	uint64_t event;
>> +	uint64_t ts;
>> +	uint64_t vector_timeout_ticks;
>> +	struct rte_mempool *vector_pool;
>> +	struct rte_event_vector *vector_ev;
>> +} __rte_cache_aligned;
>> +
>> +TAILQ_HEAD(eth_rx_vector_data_list, eth_rx_vector_data);
>> +
>>  /* Instance per adapter */
>>  struct rte_eth_event_enqueue_buffer {
>>  	/* Count of events in this buffer */
>> @@ -92,6 +110,14 @@ struct rte_event_eth_rx_adapter {
>>  	uint32_t wrr_pos;
>>  	/* Event burst buffer */
>>  	struct rte_eth_event_enqueue_buffer event_enqueue_buffer;
>> +	/* Vector enable flag */
>> +	uint8_t ena_vector;
>> +	/* Timestamp of previous vector expiry list traversal */
>> +	uint64_t prev_expiry_ts;
>> +	/* Minimum ticks to wait before traversing expiry list */
>> +	uint64_t vector_tmo_ticks;
>> +	/* vector list */
>> +	struct eth_rx_vector_data_list vector_list;
>>  	/* Per adapter stats */
>>  	struct rte_event_eth_rx_adapter_stats stats;
>>  	/* Block count, counts up to BLOCK_CNT_THRESHOLD */
>> @@ -198,9 +224,11 @@ struct eth_device_info {
>>  struct eth_rx_queue_info {
>>  	int queue_enabled;	/* True if added */
>>  	int intr_enabled;
>> +	uint8_t ena_vector;
>>  	uint16_t wt;		/* Polling weight */
>>  	uint32_t flow_id_mask;	/* Set to ~0 if app provides flow id else
>0 */
>>  	uint64_t event;
>> +	struct eth_rx_vector_data vector_data;
>>  };
>>
>>  static struct rte_event_eth_rx_adapter **event_eth_rx_adapter;
>> @@ -722,6 +750,9 @@ rxa_flush_event_buffer(struct
>rte_event_eth_rx_adapter *rx_adapter)
>>  	    &rx_adapter->event_enqueue_buffer;
>>  	struct rte_event_eth_rx_adapter_stats *stats = &rx_adapter-
>>stats;
>>
>> +	if (!buf->count)
>> +		return 0;
>> +
>>  	uint16_t n = rte_event_enqueue_new_burst(rx_adapter-
>>eventdev_id,
>>  					rx_adapter->event_port_id,
>>  					buf->events,
>> @@ -742,6 +773,72 @@ rxa_flush_event_buffer(struct
>rte_event_eth_rx_adapter *rx_adapter)
>>  	return n;
>>  }
>>
>> +static inline uint16_t
>> +rxa_create_event_vector(struct rte_event_eth_rx_adapter
>*rx_adapter,
>> +			struct eth_rx_queue_info *queue_info,
>> +			struct rte_eth_event_enqueue_buffer *buf,
>> +			struct rte_mbuf **mbufs, uint16_t num)
>> +{
>> +	struct rte_event *ev = &buf->events[buf->count];
>> +	struct eth_rx_vector_data *vec;
>> +	uint16_t filled, space, sz;
>> +
>> +	filled = 0;
>> +	vec = &queue_info->vector_data;
>> +	while (num) {
>> +		if (vec->vector_ev == NULL) {
>> +			if (rte_mempool_get(vec->vector_pool,
>> +					    (void **)&vec->vector_ev) <
>0) {
>> +				rte_pktmbuf_free_bulk(mbufs, num);
>> +				return 0;
>> +			}
>> +			vec->vector_ev->nb_elem = 0;
>> +			vec->vector_ev->port = vec->port;
>> +			vec->vector_ev->queue = vec->queue;
>> +			vec->vector_ev->attr_valid = true;
>> +			TAILQ_INSERT_TAIL(&rx_adapter->vector_list,
>vec, next);
>> +		} else if (vec->vector_ev->nb_elem == vec-
>>max_vector_count) {
>
>Is there a case where nb_elem > max_vector_count as we accumulate
>sz to it ?

I don't think so, that would overflow the vector event.

>
>> +			/* Event ready. */
>> +			ev->event = vec->event;
>> +			ev->vec = vec->vector_ev;
>> +			ev++;
>> +			filled++;
>> +			vec->vector_ev = NULL;
>> +			TAILQ_REMOVE(&rx_adapter->vector_list, vec,
>next);
>> +			if (rte_mempool_get(vec->vector_pool,
>> +					    (void **)&vec->vector_ev) <
>0) {
>> +				rte_pktmbuf_free_bulk(mbufs, num);
>> +				return 0;
>> +			}
>> +			vec->vector_ev->nb_elem = 0;
>> +			vec->vector_ev->port = vec->port;
>> +			vec->vector_ev->queue = vec->queue;
>> +			vec->vector_ev->attr_valid = true;
>> +			TAILQ_INSERT_TAIL(&rx_adapter->vector_list,
>vec, next);
>> +		}
>> +
>> +		space = vec->max_vector_count - vec->vector_ev-
>>nb_elem;
>> +		sz = num > space ? space : num;
>> +		memcpy(vec->vector_ev->mbufs + vec->vector_ev-
>>nb_elem, mbufs,
>> +		       sizeof(void *) * sz);
>> +		vec->vector_ev->nb_elem += sz;
>> +		num -= sz;
>> +		mbufs += sz;
>> +		vec->ts = rte_rdtsc();
>> +	}
>> +
>> +	if (vec->vector_ev->nb_elem == vec->max_vector_count) {
>
>Same here.
>
>> +		ev->event = vec->event;
>> +		ev->vec = vec->vector_ev;
>> +		ev++;
>> +		filled++;
>> +		vec->vector_ev = NULL;
>> +		TAILQ_REMOVE(&rx_adapter->vector_list, vec, next);
>> +	}
>> +
>> +	return filled;
>> +}
>
>I am seeing more than one repeating code chunks in this function.
>Perhaps, you can give it a try to not repeat. We can drop if its
>performance affecting.

I will try to move them to inline functions and test.

>
>> +
>>  static inline void
>>  rxa_buffer_mbufs(struct rte_event_eth_rx_adapter *rx_adapter,
>>  		uint16_t eth_dev_id,
>> @@ -770,25 +867,30 @@ rxa_buffer_mbufs(struct
>rte_event_eth_rx_adapter *rx_adapter,
>>  	rss_mask = ~(((m->ol_flags & PKT_RX_RSS_HASH) != 0) - 1);
>>  	do_rss = !rss_mask && !eth_rx_queue_info->flow_id_mask;
>
>The RSS related code is executed for vector case as well. Can this be
>moved inside ena_vector if condition ?

RSS is used to generate the event flowid, in vector case the flow id 
Will be a combination of port and queue id. 
The idea is that flows having the same RSS LSB will end up in the same 
queue.

>
>>
>> -	for (i = 0; i < num; i++) {
>> -		m = mbufs[i];
>> -
>> -		rss = do_rss ?
>> -			rxa_do_softrss(m, rx_adapter->rss_key_be) :
>> -			m->hash.rss;
>> -		ev->event = event;
>> -		ev->flow_id = (rss & ~flow_id_mask) |
>> -				(ev->flow_id & flow_id_mask);
>> -		ev->mbuf = m;
>> -		ev++;
>> +	if (!eth_rx_queue_info->ena_vector) {
>> +		for (i = 0; i < num; i++) {
>> +			m = mbufs[i];
>> +
>> +			rss = do_rss ? rxa_do_softrss(m, rx_adapter-
>>rss_key_be)
>> +				     : m->hash.rss;
>> +			ev->event = event;
>> +			ev->flow_id = (rss & ~flow_id_mask) |
>> +				      (ev->flow_id & flow_id_mask);
>> +			ev->mbuf = m;
>> +			ev++;
>> +		}
>> +	} else {
>> +		num = rxa_create_event_vector(rx_adapter,
>eth_rx_queue_info,
>> +					      buf, mbufs, num);
>>  	}
>>
>> -	if (dev_info->cb_fn) {
>> +	if (num && dev_info->cb_fn) {
>>
>>  		dropped = 0;
>>  		nb_cb = dev_info->cb_fn(eth_dev_id, rx_queue_id,
>> -					ETH_EVENT_BUFFER_SIZE, buf-
>>count, ev,
>> -					num, dev_info->cb_arg,
>&dropped);
>> +					ETH_EVENT_BUFFER_SIZE, buf-
>>count,
>> +					&buf->events[buf->count],
>num,
>> +					dev_info->cb_arg, &dropped);
>
>Before this patch, we pass ev which is &buf->events[buf->count] + num
>as fifth param when calling cb_fn. Now, we are passing &buf-
>>events[buf->count] for non-vector case. Do you see this as an issue?
>

The callback function takes in the array newly formed events i.e. we need
to pass the start of array and the count.

the previous code had a bug where it passes the end of the event list.

>Also, for vector case would it make sense to do pass &buf->events[buf-
>>count] + num ?
>
>>  		if (unlikely(nb_cb > num))
>>  			RTE_EDEV_LOG_ERR("Rx CB returned %d (> %d)
>events",
>>  				nb_cb, num);
>> @@ -1124,6 +1226,30 @@ rxa_poll(struct rte_event_eth_rx_adapter
>*rx_adapter)
>>  	return nb_rx;
>>  }
>>
>> +static void
>> +rxa_vector_expire(struct eth_rx_vector_data *vec, void *arg)
>> +{
>> +	struct rte_event_eth_rx_adapter *rx_adapter = arg;
>> +	struct rte_eth_event_enqueue_buffer *buf =
>> +		&rx_adapter->event_enqueue_buffer;
>> +	struct rte_event *ev;
>> +
>> +	if (buf->count)
>> +		rxa_flush_event_buffer(rx_adapter);
>> +
>> +	if (vec->vector_ev->nb_elem == 0)
>> +		return;
>> +	ev = &buf->events[buf->count];
>> +
>> +	/* Event ready. */
>> +	ev->event = vec->event;
>> +	ev->vec = vec->vector_ev;
>> +	buf->count++;
>> +
>> +	vec->vector_ev = NULL;
>> +	vec->ts = 0;
>> +}
>> +
>>  static int
>>  rxa_service_func(void *args)
>>  {
>> @@ -1137,6 +1263,24 @@ rxa_service_func(void *args)
>>  		return 0;
>>  	}
>>
>> +	if (rx_adapter->ena_vector) {
>> +		if ((rte_rdtsc() - rx_adapter->prev_expiry_ts) >=
>> +		    rx_adapter->vector_tmo_ticks) {
>> +			struct eth_rx_vector_data *vec;
>> +
>> +			TAILQ_FOREACH(vec, &rx_adapter->vector_list,
>next) {
>> +				uint64_t elapsed_time = rte_rdtsc() -
>vec->ts;
>> +
>> +				if (elapsed_time >= vec-
>>vector_timeout_ticks) {
>> +					rxa_vector_expire(vec,
>rx_adapter);
>> +					TAILQ_REMOVE(&rx_adapter-
>>vector_list,
>> +						     vec, next);
>> +				}
>> +			}
>> +			rx_adapter->prev_expiry_ts = rte_rdtsc();
>> +		}
>> +	}
>> +
>>  	stats = &rx_adapter->stats;
>>  	stats->rx_packets += rxa_intr_ring_dequeue(rx_adapter);
>>  	stats->rx_packets += rxa_poll(rx_adapter);
>> @@ -1640,6 +1784,28 @@ rxa_update_queue(struct
>rte_event_eth_rx_adapter *rx_adapter,
>>  	}
>>  }
>>
>> +static void
>> +rxa_set_vector_data(struct eth_rx_queue_info *queue_info,
>uint16_t vector_count,
>> +		    uint64_t vector_ns, struct rte_mempool *mp, int32_t
>qid,
>> +		    uint16_t port_id)
>> +{
>> +#define NSEC2TICK(__ns, __freq) (((__ns) * (__freq)) / 1E9)
>> +	struct eth_rx_vector_data *vector_data;
>> +	uint32_t flow_id;
>> +
>> +	vector_data = &queue_info->vector_data;
>> +	vector_data->max_vector_count = vector_count;
>> +	vector_data->port = port_id;
>> +	vector_data->queue = qid;
>> +	vector_data->vector_pool = mp;
>> +	vector_data->vector_timeout_ticks =
>> +		NSEC2TICK(vector_ns, rte_get_timer_hz());
>> +	vector_data->ts = 0;
>> +	flow_id = queue_info->event & 0xFFFFF;
>> +	flow_id = flow_id == 0 ? (qid & 0xFF) | (port_id & 0xFFFF) :
>flow_id;
>
>Maybe I am missing something here. Looking at the code it looks like
>qid and port_id may overlap. For e.g., if qid = 0x10 and port_id = 0x11,
>flow_id would end up being 0x11. Is this the expectation? Also, it may
>be useful to document flow_id format.

The flow_id is 20 bit, I guess we could do 12bit queue_id and 8bit port
as a flow.

>Comparing this format with existing RSS hash based method, are we
>saying that all mbufs received in a rx burst are part of same flow when
>vectorization is used?

Yes, the hard way to do this is to use a hash table and treating each 
mbuf having an unique flow.

>
>> +	vector_data->event = (queue_info->event & ~0xFFFFF) |
>flow_id;
>> +}
>> +
>>  static void
>>  rxa_sw_del(struct rte_event_eth_rx_adapter *rx_adapter,
>>  	struct eth_device_info *dev_info,
>> @@ -1741,6 +1907,44 @@ rxa_add_queue(struct
>rte_event_eth_rx_adapter *rx_adapter,
>>  	}
>>  }
>>
>> +static void
>> +rxa_sw_event_vector_configure(
>> +	struct rte_event_eth_rx_adapter *rx_adapter, uint16_t
>eth_dev_id,
>> +	int rx_queue_id,
>> +	const struct rte_event_eth_rx_adapter_event_vector_config
>*config)
>> +{
>> +	struct eth_device_info *dev_info = &rx_adapter-
>>eth_devices[eth_dev_id];
>> +	struct eth_rx_queue_info *queue_info;
>> +	struct rte_event *qi_ev;
>> +
>> +	if (rx_queue_id == -1) {
>> +		uint16_t nb_rx_queues;
>> +		uint16_t i;
>> +
>> +		nb_rx_queues = dev_info->dev->data->nb_rx_queues;
>> +		for (i = 0; i < nb_rx_queues; i++)
>> +			rxa_sw_event_vector_configure(rx_adapter,
>eth_dev_id, i,
>> +						      config);
>> +		return;
>> +	}
>> +
>> +	queue_info = &dev_info->rx_queue[rx_queue_id];
>> +	qi_ev = (struct rte_event *)&queue_info->event;
>> +	queue_info->ena_vector = 1;
>> +	qi_ev->event_type =
>RTE_EVENT_TYPE_ETH_RX_ADAPTER_VECTOR;
>> +	rxa_set_vector_data(queue_info, config->vector_sz,
>> +			    config->vector_timeout_ns, config-
>>vector_mp,
>> +			    rx_queue_id, dev_info->dev->data->port_id);
>> +	rx_adapter->ena_vector = 1;
>> +	rx_adapter->vector_tmo_ticks =
>> +		rx_adapter->vector_tmo_ticks ?
>> +			      RTE_MIN(config->vector_timeout_ns << 1,
>> +				      rx_adapter->vector_tmo_ticks) :
>> +			      config->vector_timeout_ns << 1;
>> +	rx_adapter->prev_expiry_ts = 0;
>> +	TAILQ_INIT(&rx_adapter->vector_list);
>> +}
>> +
>>  static int rxa_sw_add(struct rte_event_eth_rx_adapter *rx_adapter,
>>  		uint16_t eth_dev_id,
>>  		int rx_queue_id,
>> @@ -2081,6 +2285,15 @@
>rte_event_eth_rx_adapter_queue_add(uint8_t id,
>>  		return -EINVAL;
>>  	}
>>
>> +	if ((cap &
>RTE_EVENT_ETH_RX_ADAPTER_CAP_EVENT_VECTOR) == 0 &&
>> +	    (queue_conf->rx_queue_flags &
>> +	     RTE_EVENT_ETH_RX_ADAPTER_QUEUE_EVENT_VECTOR)) {
>> +		RTE_EDEV_LOG_ERR("Event vectorization is not
>supported,"
>> +				 " eth port: %" PRIu16 " adapter id: %"
>PRIu8,
>> +				 eth_dev_id, id);
>> +		return -EINVAL;
>> +	}
>> +
>>  	if ((cap &
>RTE_EVENT_ETH_RX_ADAPTER_CAP_MULTI_EVENTQ) == 0 &&
>>  		(rx_queue_id != -1)) {
>>  		RTE_EDEV_LOG_ERR("Rx queues can only be connected
>to single "
>> @@ -2143,6 +2356,17 @@
>rte_event_eth_rx_adapter_queue_add(uint8_t id,
>>  	return 0;
>>  }
>>
>> +static int
>> +rxa_sw_vector_limits(struct
>rte_event_eth_rx_adapter_vector_limits *limits)
>> +{
>> +	limits->max_sz = MAX_VECTOR_SIZE;
>> +	limits->min_sz = MIN_VECTOR_SIZE;
>> +	limits->max_timeout_ns = MAX_VECTOR_NS;
>> +	limits->min_timeout_ns = MIN_VECTOR_NS;
>> +
>> +	return 0;
>> +}
>> +
>>  int
>>  rte_event_eth_rx_adapter_queue_del(uint8_t id, uint16_t
>eth_dev_id,
>>  				int32_t rx_queue_id)
>> @@ -2333,7 +2557,8 @@
>rte_event_eth_rx_adapter_queue_event_vector_config(
>>  		ret = dev->dev_ops-
>>eth_rx_adapter_event_vector_config(
>>  			dev, &rte_eth_devices[eth_dev_id],
>rx_queue_id, config);
>>  	} else {
>> -		ret = -ENOTSUP;
>> +		rxa_sw_event_vector_configure(rx_adapter,
>eth_dev_id,
>> +					      rx_queue_id, config);
>>  	}
>>
>>  	return ret;
>> @@ -2371,7 +2596,7 @@
>rte_event_eth_rx_adapter_vector_limits_get(
>>  		ret = dev->dev_ops-
>>eth_rx_adapter_vector_limits_get(
>>  			dev, &rte_eth_devices[eth_port_id], limits);
>>  	} else {
>> -		ret = -ENOTSUP;
>> +		ret = rxa_sw_vector_limits(limits);
>>  	}
>>
>>  	return ret;
>> diff --git a/lib/librte_eventdev/rte_eventdev.c
>b/lib/librte_eventdev/rte_eventdev.c
>> index f95edc075..254a31b1f 100644
>> --- a/lib/librte_eventdev/rte_eventdev.c
>> +++ b/lib/librte_eventdev/rte_eventdev.c
>> @@ -122,7 +122,11 @@ rte_event_eth_rx_adapter_caps_get(uint8_t
>dev_id, uint16_t eth_port_id,
>>
>>  	if (caps == NULL)
>>  		return -EINVAL;
>> -	*caps = 0;
>> +
>> +	if (dev->dev_ops->eth_rx_adapter_caps_get == NULL)
>> +		*caps = RTE_EVENT_ETH_RX_ADAPTER_SW_CAP;
>> +	else
>> +		*caps = 0;
>
>Any reason why we had to set default caps value? I am thinking if sw
>event device is used, it would set it anyways.
>

There are multiple sw event devices which don't implement caps_get 
function, this changes solves that.

>>
>>  	return dev->dev_ops->eth_rx_adapter_caps_get ?
>>  				(*dev->dev_ops-
>>eth_rx_adapter_caps_get)(dev,
>> --
>> 2.17.1