Re: [PATCH v11 2/4] net/i40e: implement mbufs recycle mode

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

22/08/2023 08:27, Feifei Wang пишет:
> Define specific function implementation for i40e driver.
> Currently, mbufs recycle mode can support 128bit
> vector path and avx2 path. And can be enabled both in
> fast free and no fast free mode.
> 
> 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 +
>   .../net/i40e/i40e_recycle_mbufs_vec_common.c  | 147 ++++++++++++++++++
>   drivers/net/i40e/i40e_rxtx.c                  |  32 ++++
>   drivers/net/i40e/i40e_rxtx.h                  |   4 +
>   drivers/net/i40e/meson.build                  |   1 +
>   6 files changed, 187 insertions(+)
>   create mode 100644 drivers/net/i40e/i40e_recycle_mbufs_vec_common.c
> 
> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index 8271bbb394..50ba9aac94 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -496,6 +496,7 @@ 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,
> +	.recycle_rxq_info_get         = i40e_recycle_rxq_info_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 6f65d5e0ac..af758798e1 100644
> --- a/drivers/net/i40e/i40e_ethdev.h
> +++ b/drivers/net/i40e/i40e_ethdev.h
> @@ -1355,6 +1355,8 @@ 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_recycle_rxq_info_get(struct rte_eth_dev *dev, uint16_t queue_id,
> +	struct rte_eth_recycle_rxq_info *recycle_rxq_info);
>   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_recycle_mbufs_vec_common.c b/drivers/net/i40e/i40e_recycle_mbufs_vec_common.c
> new file mode 100644
> index 0000000000..5663ecccde
> --- /dev/null
> +++ b/drivers/net/i40e/i40e_recycle_mbufs_vec_common.c
> @@ -0,0 +1,147 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright (c) 2023 Arm Limited.
> + */
> +
> +#include <stdint.h>
> +#include <ethdev_driver.h>
> +
> +#include "base/i40e_prototype.h"
> +#include "base/i40e_type.h"
> +#include "i40e_ethdev.h"
> +#include "i40e_rxtx.h"
> +
> +#pragma GCC diagnostic ignored "-Wcast-qual"
> +
> +void
> +i40e_recycle_rx_descriptors_refill_vec(void *rx_queue, uint16_t nb_mbufs)
> +{
> +	struct i40e_rx_queue *rxq = rx_queue;
> +	struct i40e_rx_entry *rxep;
> +	volatile union i40e_rx_desc *rxdp;
> +	uint16_t rx_id;
> +	uint64_t paddr;
> +	uint64_t dma_addr;
> +	uint16_t i;
> +
> +	rxdp = rxq->rx_ring + rxq->rxrearm_start;
> +	rxep = &rxq->sw_ring[rxq->rxrearm_start];
> +
> +	for (i = 0; i < nb_mbufs; i++) {
> +		/* Initialize rxdp descs. */
> +		paddr = (rxep[i].mbuf)->buf_iova + RTE_PKTMBUF_HEADROOM;
> +		dma_addr = rte_cpu_to_le_64(paddr);
> +		/* flush desc with pa dma_addr */
> +		rxdp[i].read.hdr_addr = 0;
> +		rxdp[i].read.pkt_addr = dma_addr;
> +	}
> +
> +	/* Update the descriptor initializer index */
> +	rxq->rxrearm_start += nb_mbufs;
> +	rx_id = rxq->rxrearm_start - 1;
> +
> +	if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
> +		rxq->rxrearm_start = 0;
> +		rx_id = rxq->nb_rx_desc - 1;
> +	}
> +
> +	rxq->rxrearm_nb -= nb_mbufs;
> +
> +	rte_io_wmb();
> +	/* Update the tail pointer on the NIC */
> +	I40E_PCI_REG_WRITE_RELAXED(rxq->qrx_tail, rx_id);
> +}
> +
> +uint16_t
> +i40e_recycle_tx_mbufs_reuse_vec(void *tx_queue,
> +	struct rte_eth_recycle_rxq_info *recycle_rxq_info)
> +{
> +	struct i40e_tx_queue *txq = tx_queue;
> +	struct i40e_tx_entry *txep;
> +	struct rte_mbuf **rxep;
> +	int i, n;
> +	uint16_t nb_recycle_mbufs;
> +	uint16_t avail = 0;
> +	uint16_t mbuf_ring_size = recycle_rxq_info->mbuf_ring_size;
> +	uint16_t mask = recycle_rxq_info->mbuf_ring_size - 1;
> +	uint16_t refill_requirement = recycle_rxq_info->refill_requirement;
> +	uint16_t refill_head = *recycle_rxq_info->refill_head;
> +	uint16_t receive_tail = *recycle_rxq_info->receive_tail;
> +
> +	/* Get available recycling Rx buffers. */
> +	avail = (mbuf_ring_size - (refill_head - receive_tail)) & mask;
> +
> +	/* Check Tx free thresh and Rx available space. */
> +	if (txq->nb_tx_free > txq->tx_free_thresh || avail <= txq->tx_rs_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;
> +	nb_recycle_mbufs = n;
> +
> +	/* Mbufs recycle mode can only support no ring buffer wrapping around.
> +	 * Two case for this:
> +	 *
> +	 * case 1: The refill head of Rx buffer ring needs to be aligned with
> +	 * mbuf ring size. In this case, the number of Tx freeing buffers
> +	 * should be equal to refill_requirement.
> +	 *
> +	 * case 2: The refill head of Rx ring buffer does not need to be aligned
> +	 * with mbuf ring size. In this case, the update of refill head can not
> +	 * exceed the Rx mbuf ring size.
> +	 */
> +	if (refill_requirement != n ||
> +		(!refill_requirement && (refill_head + n > mbuf_ring_size)))
> +		return 0;
> +
> +	/* 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 = recycle_rxq_info->mbuf_ring;
> +	rxep += refill_head;
> +
> +	if (txq->offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) {
> +		/* Avoid txq contains buffers from unexpected mempool. */
> +		if (unlikely(recycle_rxq_info->mp
> +					!= txep[0].mbuf->pool))
> +			return 0;
> +
> +		/* Directly put mbufs from Tx to Rx. */
> +		for (i = 0; i < n; i++)
> +			rxep[i] = txep[i].mbuf;
> +	} else {
> +		for (i = 0; i < n; i++) {
> +			rxep[i] = rte_pktmbuf_prefree_seg(txep[i].mbuf);
> +
> +			/* If Tx buffers are not the last reference or from
> +			 * unexpected mempool, previous copied buffers are
> +			 * considered as invalid.
> +			 */
> +			if (unlikely((rxep[i] == NULL && refill_requirement) ||

Could you pls remind me why it is ok to have rxep[i]==NULL when 
refill_requirement is not set?

> +					recycle_rxq_info->mp != txep[i].mbuf->pool))
> +				nb_recycle_mbufs = 0;
> +		}
> +		/* If Tx buffers are not the last reference or
> +		 * from unexpected mempool, all recycled buffers
> +		 * are put into mempool.
> +		 */
> +		if (nb_recycle_mbufs == 0)
> +			for (i = 0; i < n; i++) {
> +				if (rxep[i] != NULL)
> +					rte_mempool_put(rxep[i]->pool, rxep[i]);
> +			}
> +	}
> +
> +	/* 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 nb_recycle_mbufs;
> +}