From 80d0759e5e714cb738c50d32edf3364b713453ff Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Tue, 13 Nov 2012 04:03:24 +0000 Subject: [PATCH] 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: Alexander Duyck Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/ethernet/intel/igb/igb_main.c | 47 +++++++++++++++---------------- 1 file changed, 22 insertions(+), 25 deletions(-) diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 0a0bd81..7044aaa 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -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); - 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); - tx_desc->read.buffer_addr = cpu_to_le64(dma); + 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(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; + size, DMA_TO_DEVICE); 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; -- 2.7.4