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Commit a292ca6e authored by Jeff Kirsher's avatar Jeff Kirsher Committed by Jeff Garzik
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[PATCH] e1000: Added copy break code 



Improves small packet performance with large amounts of reassembly being done in the stack.

Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: default avatarJohn Ronciak <john.ronciak@intel.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
parent 240b1710

drivers/net/e1000/e1000_main.c

+47 −12
Original line number Diff line number Diff line
@@ -420,7 +420,8 @@ e1000_up(struct e1000_adapter *adapter) 
	 * next_to_use != next_to_clean */

	for (i = 0; i < adapter->num_rx_queues; i++) {

		struct e1000_rx_ring *ring = &adapter->rx_ring[i];

		adapter->alloc_rx_buf(adapter, ring, E1000_DESC_UNUSED(ring));

		adapter->alloc_rx_buf(adapter, ring,

		                      E1000_DESC_UNUSED(ring));

	}



#ifdef CONFIG_PCI_MSI
@@ -3567,23 +3568,26 @@ e1000_clean_rx_irq(struct e1000_adapter *adapter, 
	uint32_t length;

	uint8_t last_byte;

	unsigned int i;

	boolean_t cleaned = FALSE;

	int cleaned_count = 0;

	boolean_t cleaned = FALSE, multi_descriptor = FALSE;



	i = rx_ring->next_to_clean;

	rx_desc = E1000_RX_DESC(*rx_ring, i);



	while(rx_desc->status & E1000_RXD_STAT_DD) {

		buffer_info = &rx_ring->buffer_info[i];

		u8 status;

#ifdef CONFIG_E1000_NAPI

		if(*work_done >= work_to_do)

			break;

		(*work_done)++;

#endif



		status = rx_desc->status;

		cleaned = TRUE;

		cleaned_count++;

		pci_unmap_single(pdev, buffer_info->dma, buffer_info->length,

		pci_unmap_single(pdev,

		                 buffer_info->dma,

		                 buffer_info->length,

		                 PCI_DMA_FROMDEVICE);



		skb = buffer_info->skb;
@@ -3602,7 +3606,8 @@ e1000_clean_rx_irq(struct e1000_adapter *adapter, 
			if(TBI_ACCEPT(&adapter->hw, rx_desc->status,

			              rx_desc->errors, length, last_byte)) {

				spin_lock_irqsave(&adapter->stats_lock, flags);

				e1000_tbi_adjust_stats(&adapter->hw, &adapter->stats,

				e1000_tbi_adjust_stats(&adapter->hw,

				                       &adapter->stats,

				                       length, skb->data);

				spin_unlock_irqrestore(&adapter->stats_lock,

				                       flags);
@@ -3613,17 +3618,40 @@ e1000_clean_rx_irq(struct e1000_adapter *adapter, 
			}

		}



		/* Good Receive */

		skb_put(skb, length - ETHERNET_FCS_SIZE);

		/* code added for copybreak, this should improve

		 * performance for small packets with large amounts

		 * of reassembly being done in the stack */

#define E1000_CB_LENGTH 256

		if ((length < E1000_CB_LENGTH) &&

		   !rx_ring->rx_skb_top &&

		   /* or maybe (status & E1000_RXD_STAT_EOP) && */

		   !multi_descriptor) {

			struct sk_buff *new_skb =

			    dev_alloc_skb(length + NET_IP_ALIGN);

			if (new_skb) {

				skb_reserve(new_skb, NET_IP_ALIGN);

				new_skb->dev = netdev;

				memcpy(new_skb->data - NET_IP_ALIGN,

				       skb->data - NET_IP_ALIGN,

				       length + NET_IP_ALIGN);

				/* save the skb in buffer_info as good */

				buffer_info->skb = skb;

				skb = new_skb;

				skb_put(skb, length);

			}

		}



		/* end copybreak code */



		/* Receive Checksum Offload */

		e1000_rx_checksum(adapter, (uint32_t)(rx_desc->status) |

		e1000_rx_checksum(adapter,

				  (uint32_t)(status) |

				  ((uint32_t)(rx_desc->errors) << 24),

				  rx_desc->csum, skb);

		skb->protocol = eth_type_trans(skb, netdev);

#ifdef CONFIG_E1000_NAPI

		if(unlikely(adapter->vlgrp &&

			    (rx_desc->status & E1000_RXD_STAT_VP))) {

			    (status & E1000_RXD_STAT_VP))) {

			vlan_hwaccel_receive_skb(skb, adapter->vlgrp,

						 le16_to_cpu(rx_desc->special) &

						 E1000_RXD_SPC_VLAN_MASK);
@@ -3830,8 +3858,14 @@ e1000_alloc_rx_buffers(struct e1000_adapter *adapter, 
	i = rx_ring->next_to_use;

	buffer_info = &rx_ring->buffer_info[i];



	while(!buffer_info->skb) {

	while (cleaned_count--) {

		if (!(skb = buffer_info->skb))

			skb = dev_alloc_skb(bufsz);

		else {

			skb_trim(skb, 0);

			goto map_skb;

		}





		if(unlikely(!skb)) {

			/* Better luck next round */
@@ -3872,6 +3906,7 @@ e1000_alloc_rx_buffers(struct e1000_adapter *adapter, 


		buffer_info->skb = skb;

		buffer_info->length = adapter->rx_buffer_len;

map_skb:

		buffer_info->dma = pci_map_single(pdev,

						  skb->data,

						  adapter->rx_buffer_len,