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Commit ec718254 authored by Alexander Duyck's avatar Alexander Duyck Committed by Jeff Kirsher
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ixgbe: Improve performance and reduce size of ixgbe_tx_map 



This change is meant to both improve the performance and reduce the size of
ixgbe_tx_map.  To do this I have expanded the work done in the main loop by
pushing first into tx_buffer.  This allows us to pull in the dma_mapping_error
check, the tx_buffer value assignment, and the initial DMA value assignment to
the Tx descriptor.  The net result is that the function reduces in size by a
little over a 100 bytes and is about 1% or 2% faster.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Tested-by: default avatarPhil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 472148c3

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

+19 −23
Original line number Diff line number Diff line
@@ -6091,21 +6091,22 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, 
			 struct ixgbe_tx_buffer *first,

			 const u8 hdr_len)

{

	dma_addr_t dma;

	struct sk_buff *skb = first->skb;

	struct ixgbe_tx_buffer *tx_buffer;

	union ixgbe_adv_tx_desc *tx_desc;

	struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];

	unsigned int data_len = skb->data_len;

	unsigned int size = skb_headlen(skb);

	unsigned int paylen = skb->len - hdr_len;

	struct skb_frag_struct *frag;

	dma_addr_t dma;

	unsigned int data_len, size;

	u32 tx_flags = first->tx_flags;

	u32 cmd_type = ixgbe_tx_cmd_type(skb, tx_flags);

	u16 i = tx_ring->next_to_use;



	tx_desc = IXGBE_TX_DESC(tx_ring, i);



	ixgbe_tx_olinfo_status(tx_desc, tx_flags, paylen);

	ixgbe_tx_olinfo_status(tx_desc, tx_flags, skb->len - hdr_len);



	size = skb_headlen(skb);

	data_len = skb->data_len;



#ifdef IXGBE_FCOE

	if (tx_flags & IXGBE_TX_FLAGS_FCOE) {
@@ -6119,16 +6120,19 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, 


#endif

	dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);



	tx_buffer = first;



	for (frag = &skb_shinfo(skb)->frags[0];; frag++) {

		if (dma_mapping_error(tx_ring->dev, dma))

			goto dma_error;



		/* record length, and DMA address */

	dma_unmap_len_set(first, len, size);

	dma_unmap_addr_set(first, dma, dma);

		dma_unmap_len_set(tx_buffer, len, size);

		dma_unmap_addr_set(tx_buffer, dma, dma);



		tx_desc->read.buffer_addr = cpu_to_le64(dma);



	for (;;) {

		while (unlikely(size > IXGBE_MAX_DATA_PER_TXD)) {

			tx_desc->read.cmd_type_len =

				cpu_to_le32(cmd_type ^ IXGBE_MAX_DATA_PER_TXD);
@@ -6139,12 +6143,12 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, 
				tx_desc = IXGBE_TX_DESC(tx_ring, 0);

				i = 0;

			}

			tx_desc->read.olinfo_status = 0;



			dma += IXGBE_MAX_DATA_PER_TXD;

			size -= IXGBE_MAX_DATA_PER_TXD;



			tx_desc->read.buffer_addr = cpu_to_le64(dma);

			tx_desc->read.olinfo_status = 0;

		}



		if (likely(!data_len))
@@ -6158,6 +6162,7 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, 
			tx_desc = IXGBE_TX_DESC(tx_ring, 0);

			i = 0;

		}

		tx_desc->read.olinfo_status = 0;



#ifdef IXGBE_FCOE

		size = min_t(unsigned int, data_len, skb_frag_size(frag));
@@ -6168,17 +6173,8 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, 


		dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size,

				       DMA_TO_DEVICE);

		if (dma_mapping_error(tx_ring->dev, dma))

			goto dma_error;



		tx_buffer = &tx_ring->tx_buffer_info[i];

		dma_unmap_len_set(tx_buffer, len, size);

		dma_unmap_addr_set(tx_buffer, dma, dma);



		tx_desc->read.buffer_addr = cpu_to_le64(dma);

		tx_desc->read.olinfo_status = 0;



		frag++;

	}



	/* write last descriptor with RS and EOP bits */