Re: [PATCH v3 2/3] net/i40e: enable direct rearm with separate API

[Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>]

04/01/2023 07:30, Feifei Wang пишет:
> Add internal API to separate direct rearm operations between
> Rx and Tx.
> 
> Suggested-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> ---
>   drivers/net/i40e/i40e_ethdev.c          |  1 +
>   drivers/net/i40e/i40e_ethdev.h          |  2 +
>   drivers/net/i40e/i40e_rxtx.c            | 19 +++++++++
>   drivers/net/i40e/i40e_rxtx.h            |  4 ++
>   drivers/net/i40e/i40e_rxtx_vec_common.h | 54 +++++++++++++++++++++++++
>   drivers/net/i40e/i40e_rxtx_vec_neon.c   | 42 +++++++++++++++++++
>   6 files changed, 122 insertions(+)
> 
> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index 7726a89d99..29c1ce2470 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -497,6 +497,7 @@ static const struct eth_dev_ops i40e_eth_dev_ops = {
>   	.flow_ops_get                 = i40e_dev_flow_ops_get,
>   	.rxq_info_get                 = i40e_rxq_info_get,
>   	.txq_info_get                 = i40e_txq_info_get,
> +	.rxq_rearm_data_get           = i40e_rxq_rearm_data_get,
>   	.rx_burst_mode_get            = i40e_rx_burst_mode_get,
>   	.tx_burst_mode_get            = i40e_tx_burst_mode_get,
>   	.timesync_enable              = i40e_timesync_enable,
> diff --git a/drivers/net/i40e/i40e_ethdev.h b/drivers/net/i40e/i40e_ethdev.h
> index fe943a45ff..6a6a2a6d3c 100644
> --- a/drivers/net/i40e/i40e_ethdev.h
> +++ b/drivers/net/i40e/i40e_ethdev.h
> @@ -1352,6 +1352,8 @@ void i40e_rxq_info_get(struct rte_eth_dev *dev, uint16_t queue_id,
>   	struct rte_eth_rxq_info *qinfo);
>   void i40e_txq_info_get(struct rte_eth_dev *dev, uint16_t queue_id,
>   	struct rte_eth_txq_info *qinfo);
> +void i40e_rxq_rearm_data_get(struct rte_eth_dev *dev, uint16_t queue_id,
> +	struct rte_eth_rxq_rearm_data *rxq_rearm_data);
>   int i40e_rx_burst_mode_get(struct rte_eth_dev *dev, uint16_t queue_id,
>   			   struct rte_eth_burst_mode *mode);
>   int i40e_tx_burst_mode_get(struct rte_eth_dev *dev, uint16_t queue_id,
> diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
> index 788ffb51c2..d8d801acaf 100644
> --- a/drivers/net/i40e/i40e_rxtx.c
> +++ b/drivers/net/i40e/i40e_rxtx.c
> @@ -3197,6 +3197,19 @@ i40e_txq_info_get(struct rte_eth_dev *dev, uint16_t queue_id,
>   	qinfo->conf.offloads = txq->offloads;
>   }
>   
> +void
> +i40e_rxq_rearm_data_get(struct rte_eth_dev *dev, uint16_t queue_id,
> +	struct rte_eth_rxq_rearm_data *rxq_rearm_data)
> +{
> +	struct i40e_rx_queue *rxq;
> +
> +	rxq = dev->data->rx_queues[queue_id];
> +
> +	rxq_rearm_data->rx_sw_ring = rxq->sw_ring;
> +	rxq_rearm_data->rearm_start = &rxq->rxrearm_start;
> +	rxq_rearm_data->rearm_nb = &rxq->rxrearm_nb;
> +}
> +
>   #ifdef RTE_ARCH_X86
>   static inline bool
>   get_avx_supported(bool request_avx512)
> @@ -3321,6 +3334,9 @@ i40e_set_rx_function(struct rte_eth_dev *dev)
>   			PMD_INIT_LOG(DEBUG, "Using Vector Rx (port %d).",
>   				     dev->data->port_id);
>   			dev->rx_pkt_burst = i40e_recv_pkts_vec;
> +#ifdef RTE_ARCH_ARM64
> +			dev->rx_flush_descriptor = i40e_rx_flush_descriptor_vec;
> +#endif
>   		}
>   #endif /* RTE_ARCH_X86 */
>   	} else if (!dev->data->scattered_rx && ad->rx_bulk_alloc_allowed) {
> @@ -3484,6 +3500,9 @@ i40e_set_tx_function(struct rte_eth_dev *dev)
>   			PMD_INIT_LOG(DEBUG, "Using Vector Tx (port %d).",
>   				     dev->data->port_id);
>   			dev->tx_pkt_burst = i40e_xmit_pkts_vec;
> +#ifdef RTE_ARCH_ARM64
> +			dev->tx_fill_sw_ring = i40e_tx_fill_sw_ring;
> +#endif

As I can see tx_fill_sw_ring() is non ARM specific, any reason to guard 
it with #ifdef ARM?
Actually same ask for rx_flush_descriptor() - can we have generic 
version too?

>   #endif /* RTE_ARCH_X86 */
>   		} else {
>   			PMD_INIT_LOG(DEBUG, "Simple tx finally be used.");
> diff --git a/drivers/net/i40e/i40e_rxtx.h b/drivers/net/i40e/i40e_rxtx.h
> index 5e6eecc501..8a29bd89df 100644
> --- a/drivers/net/i40e/i40e_rxtx.h
> +++ b/drivers/net/i40e/i40e_rxtx.h
> @@ -233,6 +233,10 @@ uint32_t i40e_dev_rx_queue_count(void *rx_queue);
>   int i40e_dev_rx_descriptor_status(void *rx_queue, uint16_t offset);
>   int i40e_dev_tx_descriptor_status(void *tx_queue, uint16_t offset);
>   
> +int i40e_tx_fill_sw_ring(void *tx_queue,
> +		struct rte_eth_rxq_rearm_data *rxq_rearm_data);
> +int i40e_rx_flush_descriptor_vec(void *rx_queue, uint16_t nb_rearm);
> +
>   uint16_t i40e_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>   			    uint16_t nb_pkts);
>   uint16_t i40e_recv_scattered_pkts_vec(void *rx_queue,
> diff --git a/drivers/net/i40e/i40e_rxtx_vec_common.h b/drivers/net/i40e/i40e_rxtx_vec_common.h
> index fe1a6ec75e..eb96301a43 100644
> --- a/drivers/net/i40e/i40e_rxtx_vec_common.h
> +++ b/drivers/net/i40e/i40e_rxtx_vec_common.h
> @@ -146,6 +146,60 @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
>   	return txq->tx_rs_thresh;
>   }
>   
> +int
> +i40e_tx_fill_sw_ring(void *tx_queue,
> +		struct rte_eth_rxq_rearm_data *rxq_rearm_data)
> +{
> +	struct i40e_tx_queue *txq = tx_queue;
> +	struct i40e_tx_entry *txep;
> +	void **rxep;
> +	struct rte_mbuf *m;
> +	int i, n;
> +	int nb_rearm = 0;
> +
> +	if (*rxq_rearm_data->rearm_nb < txq->tx_rs_thresh ||
> +			txq->nb_tx_free > txq->tx_free_thresh)
> +		return 0;
> +
> +	/* check DD bits on threshold descriptor */
> +	if ((txq->tx_ring[txq->tx_next_dd].cmd_type_offset_bsz &
> +			rte_cpu_to_le_64(I40E_TXD_QW1_DTYPE_MASK)) !=
> +			rte_cpu_to_le_64(I40E_TX_DESC_DTYPE_DESC_DONE))
> +		return 0;
> +
> +	n = txq->tx_rs_thresh;
> +
> +	/* first buffer to free from S/W ring is at index
> +	 * tx_next_dd - (tx_rs_thresh-1)
> +	 */
> +	txep = &txq->sw_ring[txq->tx_next_dd - (n - 1)];
> +	rxep = rxq_rearm_data->rx_sw_ring;
> +	rxep += *rxq_rearm_data->rearm_start;
> +
> +	if (txq->offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) {
> +		/* directly put mbufs from Tx to Rx */
> +		for (i = 0; i < n; i++, rxep++, txep++)
> +			*rxep = txep[0].mbuf;
> +	} else {
> +		for (i = 0; i < n; i++, rxep++) {
> +			m = rte_pktmbuf_prefree_seg(txep[i].mbuf);
> +			if (m != NULL) {
> +				*rxep = m;
> +				nb_rearm++;
> +			}
> +		}
> +		n = nb_rearm;
> +	}
> +
> +	/* update counters for Tx */
> +	txq->nb_tx_free = (uint16_t)(txq->nb_tx_free + txq->tx_rs_thresh);
> +	txq->tx_next_dd = (uint16_t)(txq->tx_next_dd + txq->tx_rs_thresh);
> +	if (txq->tx_next_dd >= txq->nb_tx_desc)
> +		txq->tx_next_dd = (uint16_t)(txq->tx_rs_thresh - 1);
> +
> +	return n;
> +}
> +
>   static __rte_always_inline void
>   tx_backlog_entry(struct i40e_tx_entry *txep,
>   		 struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
> diff --git a/drivers/net/i40e/i40e_rxtx_vec_neon.c b/drivers/net/i40e/i40e_rxtx_vec_neon.c
> index 12e6f1cbcb..1509d3223b 100644
> --- a/drivers/net/i40e/i40e_rxtx_vec_neon.c
> +++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c
> @@ -739,6 +739,48 @@ i40e_xmit_fixed_burst_vec(void *__rte_restrict tx_queue,
>   	return nb_pkts;
>   }
>   
> +int
> +i40e_rx_flush_descriptor_vec(void *rx_queue, uint16_t nb_rearm)
> +{
> +	struct i40e_rx_queue *rxq = rx_queue;
> +	struct i40e_rx_entry *rxep;
> +	volatile union i40e_rx_desc *rxdp;
> +	uint16_t rx_id;
> +	uint64x2_t dma_addr;
> +	uint64_t paddr;
> +	uint16_t i;
> +
> +	rxdp = rxq->rx_ring + rxq->rxrearm_start;
> +	rxep = &rxq->sw_ring[rxq->rxrearm_start];
> +
> +	for (i = 0; i < nb_rearm; i++) {
> +		/* Initialize rxdp descs */
> +		paddr = (rxep[i].mbuf)->buf_iova + RTE_PKTMBUF_HEADROOM;
> +		dma_addr = vdupq_n_u64(paddr);
> +		/* flush desc with pa dma_addr */
> +		vst1q_u64((uint64_t *)&rxdp++->read, dma_addr);
> +	}
> +
> +	/* Update the descriptor initializer index */
> +	rxq->rxrearm_start += nb_rearm;
> +	rx_id = rxq->rxrearm_start - 1;
> +
> +	if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
> +		rxq->rxrearm_start = rxq->rxrearm_start - rxq->nb_rx_desc;
> +		if (!rxq->rxrearm_start)
> +			rx_id = rxq->nb_rx_desc - 1;
> +		else
> +			rx_id = rxq->rxrearm_start - 1;
> +	}
> +	rxq->rxrearm_nb -= nb_rearm;
> +
> +	rte_io_wmb();
> +	/* Update the tail pointer on the NIC */
> +	I40E_PCI_REG_WRITE_RELAXED(rxq->qrx_tail, rx_id);
> +
> +	return 0;
> +}
> +
>   void __rte_cold
>   i40e_rx_queue_release_mbufs_vec(struct i40e_rx_queue *rxq)
>   {