Commit af6f4791 authored by Wei Fang's avatar Wei Fang Committed by David S. Miller
Browse files

net: fec: improve XDP_TX performance 



As suggested by Jesper and Alexander, we can avoid converting xdp_buff
to xdp_frame in case of XDP_TX to save a bunch of CPU cycles, so that
we can further improve the XDP_TX performance.

Before this patch on i.MX8MP-EVK board, the performance shows as follows.
root@imx8mpevk:~# ./xdp2 eth0
proto 17:     353918 pkt/s
proto 17:     352923 pkt/s
proto 17:     353900 pkt/s
proto 17:     352672 pkt/s
proto 17:     353912 pkt/s
proto 17:     354219 pkt/s

After applying this patch, the performance is improved.
root@imx8mpevk:~# ./xdp2 eth0
proto 17:     369261 pkt/s
proto 17:     369267 pkt/s
proto 17:     369206 pkt/s
proto 17:     369214 pkt/s
proto 17:     369126 pkt/s
proto 17:     369272 pkt/s

Signed-off-by: default avatarWei Fang <wei.fang@nxp.com>
Suggested-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Suggested-by: default avatarJesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: default avatarJesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f601899e

drivers/net/ethernet/freescale/fec.h

+1 −4
Original line number Diff line number Diff line
@@ -552,10 +552,7 @@ enum fec_txbuf_type { 
};



struct fec_tx_buffer {

	union {

		struct sk_buff *skb;

		struct xdp_frame *xdp;

	};

	void *buf_p;

	enum fec_txbuf_type type;

};

drivers/net/ethernet/freescale/fec_main.c

+74 −66
Original line number Diff line number Diff line
@@ -400,7 +400,7 @@ static void fec_dump(struct net_device *ndev) 
			fec16_to_cpu(bdp->cbd_sc),

			fec32_to_cpu(bdp->cbd_bufaddr),

			fec16_to_cpu(bdp->cbd_datlen),

			txq->tx_buf[index].skb);

			txq->tx_buf[index].buf_p);

		bdp = fec_enet_get_nextdesc(bdp, &txq->bd);

		index++;

	} while (bdp != txq->bd.base);
@@ -657,7 +657,7 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq, 


	index = fec_enet_get_bd_index(last_bdp, &txq->bd);

	/* Save skb pointer */

	txq->tx_buf[index].skb = skb;

	txq->tx_buf[index].buf_p = skb;



	/* Make sure the updates to rest of the descriptor are performed before

	 * transferring ownership.
@@ -863,7 +863,7 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq, 
	}



	/* Save skb pointer */

	txq->tx_buf[index].skb = skb;

	txq->tx_buf[index].buf_p = skb;



	skb_tx_timestamp(skb);

	txq->bd.cur = bdp;
@@ -960,27 +960,27 @@ static void fec_enet_bd_init(struct net_device *dev) 
							 fec32_to_cpu(bdp->cbd_bufaddr),

							 fec16_to_cpu(bdp->cbd_datlen),

							 DMA_TO_DEVICE);

				if (txq->tx_buf[i].skb) {

					dev_kfree_skb_any(txq->tx_buf[i].skb);

					txq->tx_buf[i].skb = NULL;

				}

			} else {

				if (bdp->cbd_bufaddr &&

				    txq->tx_buf[i].type == FEC_TXBUF_T_XDP_NDO)

				if (txq->tx_buf[i].buf_p)

					dev_kfree_skb_any(txq->tx_buf[i].buf_p);

			} else if (txq->tx_buf[i].type == FEC_TXBUF_T_XDP_NDO) {

				if (bdp->cbd_bufaddr)

					dma_unmap_single(&fep->pdev->dev,

							 fec32_to_cpu(bdp->cbd_bufaddr),

							 fec16_to_cpu(bdp->cbd_datlen),

							 DMA_TO_DEVICE);



				if (txq->tx_buf[i].xdp) {

					xdp_return_frame(txq->tx_buf[i].xdp);

					txq->tx_buf[i].xdp = NULL;

				if (txq->tx_buf[i].buf_p)

					xdp_return_frame(txq->tx_buf[i].buf_p);

			} else {

				struct page *page = txq->tx_buf[i].buf_p;



				if (page)

					page_pool_put_page(page->pp, page, 0, false);

			}



			txq->tx_buf[i].buf_p = NULL;

			/* restore default tx buffer type: FEC_TXBUF_T_SKB */

			txq->tx_buf[i].type = FEC_TXBUF_T_SKB;

			}



			bdp->cbd_bufaddr = cpu_to_fec32(0);

			bdp = fec_enet_get_nextdesc(bdp, &txq->bd);

		}
@@ -1387,6 +1387,8 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id, int budget) 
	struct netdev_queue *nq;

	int	index = 0;

	int	entries_free;

	struct page *page;

	int frame_len;



	fep = netdev_priv(ndev);
@@ -1408,8 +1410,7 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id, int budget) 
		index = fec_enet_get_bd_index(bdp, &txq->bd);



		if (txq->tx_buf[index].type == FEC_TXBUF_T_SKB) {

			skb = txq->tx_buf[index].skb;

			txq->tx_buf[index].skb = NULL;

			skb = txq->tx_buf[index].buf_p;

			if (bdp->cbd_bufaddr &&

			    !IS_TSO_HEADER(txq, fec32_to_cpu(bdp->cbd_bufaddr)))

				dma_unmap_single(&fep->pdev->dev,
@@ -1428,18 +1429,24 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id, int budget) 
			if (unlikely(!budget))

				break;



			xdpf = txq->tx_buf[index].xdp;

			if (bdp->cbd_bufaddr &&

			    txq->tx_buf[index].type == FEC_TXBUF_T_XDP_NDO)

			if (txq->tx_buf[index].type == FEC_TXBUF_T_XDP_NDO) {

				xdpf = txq->tx_buf[index].buf_p;

				if (bdp->cbd_bufaddr)

					dma_unmap_single(&fep->pdev->dev,

							 fec32_to_cpu(bdp->cbd_bufaddr),

							 fec16_to_cpu(bdp->cbd_datlen),

							 DMA_TO_DEVICE);

			} else {

				page = txq->tx_buf[index].buf_p;

			}



			bdp->cbd_bufaddr = cpu_to_fec32(0);

			if (unlikely(!xdpf)) {

			if (unlikely(!txq->tx_buf[index].buf_p)) {

				txq->tx_buf[index].type = FEC_TXBUF_T_SKB;

				goto tx_buf_done;

			}



			frame_len = fec16_to_cpu(bdp->cbd_datlen);

		}



		/* Check for errors. */
@@ -1463,7 +1470,7 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id, int budget) 
			if (txq->tx_buf[index].type == FEC_TXBUF_T_SKB)

				ndev->stats.tx_bytes += skb->len;

			else

				ndev->stats.tx_bytes += xdpf->len;

				ndev->stats.tx_bytes += frame_len;

		}



		/* Deferred means some collisions occurred during transmit,
@@ -1488,22 +1495,16 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id, int budget) 


			/* Free the sk buffer associated with this last transmit */

			dev_kfree_skb_any(skb);

		} else {

			if (txq->tx_buf[index].type == FEC_TXBUF_T_XDP_NDO) {

		} else if (txq->tx_buf[index].type == FEC_TXBUF_T_XDP_NDO) {

			xdp_return_frame_rx_napi(xdpf);

		} else { /* recycle pages of XDP_TX frames */

				struct page *page = virt_to_head_page(xdpf->data);



				/* The dma_sync_size = 0 as XDP_TX has already

				 * synced DMA for_device.

				 */

			/* The dma_sync_size = 0 as XDP_TX has already synced DMA for_device */

			page_pool_put_page(page->pp, page, 0, true);

		}



			txq->tx_buf[index].xdp = NULL;

		txq->tx_buf[index].buf_p = NULL;

		/* restore default tx buffer type: FEC_TXBUF_T_SKB */

		txq->tx_buf[index].type = FEC_TXBUF_T_SKB;

		}



tx_buf_done:

		/* Make sure the update to bdp and tx_buf are performed
@@ -3234,7 +3235,6 @@ static void fec_enet_free_buffers(struct net_device *ndev) 
{

	struct fec_enet_private *fep = netdev_priv(ndev);

	unsigned int i;

	struct sk_buff *skb;

	struct fec_enet_priv_tx_q *txq;

	struct fec_enet_priv_rx_q *rxq;

	unsigned int q;
@@ -3259,21 +3259,26 @@ static void fec_enet_free_buffers(struct net_device *ndev) 
			kfree(txq->tx_bounce[i]);

			txq->tx_bounce[i] = NULL;



			if (!txq->tx_buf[i].buf_p) {

				txq->tx_buf[i].type = FEC_TXBUF_T_SKB;

				continue;

			}



			if (txq->tx_buf[i].type == FEC_TXBUF_T_SKB) {

				skb = txq->tx_buf[i].skb;

				txq->tx_buf[i].skb = NULL;

				dev_kfree_skb(skb);

				dev_kfree_skb(txq->tx_buf[i].buf_p);

			} else if (txq->tx_buf[i].type == FEC_TXBUF_T_XDP_NDO) {

				xdp_return_frame(txq->tx_buf[i].buf_p);

			} else {

				if (txq->tx_buf[i].xdp) {

					xdp_return_frame(txq->tx_buf[i].xdp);

					txq->tx_buf[i].xdp = NULL;

				struct page *page = txq->tx_buf[i].buf_p;



				page_pool_put_page(page->pp, page, 0, false);

			}



			txq->tx_buf[i].buf_p = NULL;

			txq->tx_buf[i].type = FEC_TXBUF_T_SKB;

		}

	}

}

}



static void fec_enet_free_queue(struct net_device *ndev)

{
@@ -3793,13 +3798,14 @@ fec_enet_xdp_get_tx_queue(struct fec_enet_private *fep, int index) 


static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep,

				   struct fec_enet_priv_tx_q *txq,

				   struct xdp_frame *frame,

				   u32 dma_sync_len, bool ndo_xmit)

				   void *frame, u32 dma_sync_len,

				   bool ndo_xmit)

{

	unsigned int index, status, estatus;

	struct bufdesc *bdp;

	dma_addr_t dma_addr;

	int entries_free;

	u16 frame_len;



	entries_free = fec_enet_get_free_txdesc_num(txq);

	if (entries_free < MAX_SKB_FRAGS + 1) {
@@ -3815,30 +3821,36 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep, 
	index = fec_enet_get_bd_index(bdp, &txq->bd);



	if (ndo_xmit) {

		dma_addr = dma_map_single(&fep->pdev->dev, frame->data,

					  frame->len, DMA_TO_DEVICE);

		struct xdp_frame *xdpf = frame;



		dma_addr = dma_map_single(&fep->pdev->dev, xdpf->data,

					  xdpf->len, DMA_TO_DEVICE);

		if (dma_mapping_error(&fep->pdev->dev, dma_addr))

			return -ENOMEM;



		frame_len = xdpf->len;

		txq->tx_buf[index].buf_p = xdpf;

		txq->tx_buf[index].type = FEC_TXBUF_T_XDP_NDO;

	} else {

		struct page *page = virt_to_page(frame->data);

		struct xdp_buff *xdpb = frame;

		struct page *page;



		dma_addr = page_pool_get_dma_addr(page) + sizeof(*frame) +

			   frame->headroom;

		page = virt_to_page(xdpb->data);

		dma_addr = page_pool_get_dma_addr(page) +

			   (xdpb->data - xdpb->data_hard_start);

		dma_sync_single_for_device(&fep->pdev->dev, dma_addr,

					   dma_sync_len, DMA_BIDIRECTIONAL);

		frame_len = xdpb->data_end - xdpb->data;

		txq->tx_buf[index].buf_p = page;

		txq->tx_buf[index].type = FEC_TXBUF_T_XDP_TX;

	}



	txq->tx_buf[index].xdp = frame;



	status |= (BD_ENET_TX_INTR | BD_ENET_TX_LAST);

	if (fep->bufdesc_ex)

		estatus = BD_ENET_TX_INT;



	bdp->cbd_bufaddr = cpu_to_fec32(dma_addr);

	bdp->cbd_datlen = cpu_to_fec16(frame->len);

	bdp->cbd_datlen = cpu_to_fec16(frame_len);



	if (fep->bufdesc_ex) {

		struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
@@ -3879,14 +3891,10 @@ static int fec_enet_xdp_tx_xmit(struct fec_enet_private *fep, 
				int cpu, struct xdp_buff *xdp,

				u32 dma_sync_len)

{

	struct xdp_frame *xdpf = xdp_convert_buff_to_frame(xdp);

	struct fec_enet_priv_tx_q *txq;

	struct netdev_queue *nq;

	int queue, ret;



	if (unlikely(!xdpf))

		return -EFAULT;



	queue = fec_enet_xdp_get_tx_queue(fep, cpu);

	txq = fep->tx_queue[queue];

	nq = netdev_get_tx_queue(fep->netdev, queue);
@@ -3895,7 +3903,7 @@ static int fec_enet_xdp_tx_xmit(struct fec_enet_private *fep, 


	/* Avoid tx timeout as XDP shares the queue with kernel stack */

	txq_trans_cond_update(nq);

	ret = fec_enet_txq_xmit_frame(fep, txq, xdpf, dma_sync_len, false);

	ret = fec_enet_txq_xmit_frame(fep, txq, xdp, dma_sync_len, false);



	__netif_tx_unlock(nq);