Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 80d0759e authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

igb: Improve performance and reduce size of igb_tx_map 



This change is meant to both improve the performance and reduce the size of
igb_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 avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1d9daf45

drivers/net/ethernet/intel/igb/igb_main.c

+22 −25
Original line number Diff line number Diff line
@@ -4188,29 +4188,34 @@ static void igb_tx_map(struct igb_ring *tx_ring, 
	struct sk_buff *skb = first->skb;

	struct igb_tx_buffer *tx_buffer;

	union e1000_adv_tx_desc *tx_desc;

	struct skb_frag_struct *frag;

	dma_addr_t dma;

	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;

	unsigned int data_len, size;

	u32 tx_flags = first->tx_flags;

	u32 cmd_type = igb_tx_cmd_type(skb, tx_flags);

	u16 i = tx_ring->next_to_use;



	tx_desc = IGB_TX_DESC(tx_ring, i);



	igb_tx_olinfo_status(tx_ring, tx_desc, tx_flags, paylen);

	igb_tx_olinfo_status(tx_ring, tx_desc, tx_flags, skb->len - hdr_len);



	size = skb_headlen(skb);

	data_len = skb->data_len;



	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 > IGB_MAX_DATA_PER_TXD)) {

			tx_desc->read.cmd_type_len =

				cpu_to_le32(cmd_type ^ IGB_MAX_DATA_PER_TXD);
@@ -4221,11 +4226,11 @@ static void igb_tx_map(struct igb_ring *tx_ring, 
				tx_desc = IGB_TX_DESC(tx_ring, 0);

				i = 0;

			}

			tx_desc->read.olinfo_status = 0;



			dma += IGB_MAX_DATA_PER_TXD;

			size -= IGB_MAX_DATA_PER_TXD;



			tx_desc->read.olinfo_status = 0;

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

		}
@@ -4240,31 +4245,23 @@ static void igb_tx_map(struct igb_ring *tx_ring, 
			tx_desc = IGB_TX_DESC(tx_ring, 0);

			i = 0;

		}

		tx_desc->read.olinfo_status = 0;



		size = skb_frag_size(frag);

		data_len -= size;



		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.olinfo_status = 0;

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



		frag++;

	}



	netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);



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

	cmd_type |= size | IGB_TXD_DCMD;

	tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);



	netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);



	/* set the timestamp */

	first->time_stamp = jiffies;