Commit ad829268 authored by Matt Carlson's avatar Matt Carlson Committed by David S. Miller
Browse files

tg3: Use NET_IP_ALIGN 



This patch replaces hardcoded 2's with the NET_IP_ALIGN constant or
TG3_RAW_IP_ALIGN where appropriate.  Some platforms can redefine the
NET_IP_ALIGN definition to zero if unaligned DMA transfers cost more
than the IP header alignment gains.  This patch represents a
performance improvement when using the 5701 on these platforms.
The copy path can be avoided.

TG3_RAW_IP_ALIGN is used in cases where we always want to align the
IP header on dword boundaries.

Signed-off-by: default avatarMatt Carlson <mcarlson@broadcom.com>
Signed-off-by: default avatarMichael Chan <mchan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cf005b1d

drivers/net/tg3.c

+13 −7
Original line number Diff line number Diff line
@@ -132,6 +132,8 @@ 
/* minimum number of free TX descriptors required to wake up TX process */

#define TG3_TX_WAKEUP_THRESH(tp)		((tp)->tx_pending / 4)



#define TG3_RAW_IP_ALIGN 2



/* number of ETHTOOL_GSTATS u64's */

#define TG3_NUM_STATS		(sizeof(struct tg3_ethtool_stats)/sizeof(u64))
@@ -4231,12 +4233,15 @@ static int tg3_rx(struct tg3 *tp, int budget) 
			goto next_pkt;

		}



		len = ((desc->idx_len & RXD_LEN_MASK) >> RXD_LEN_SHIFT) - 4; /* omit crc */

		len = ((desc->idx_len & RXD_LEN_MASK) >> RXD_LEN_SHIFT) -

		      ETH_FCS_LEN;



		if (len > RX_COPY_THRESHOLD

			&& tp->rx_offset == 2

			/* rx_offset != 2 iff this is a 5701 card running

			 * in PCI-X mode [see tg3_get_invariants()] */

			&& tp->rx_offset == NET_IP_ALIGN

			/* rx_offset will likely not equal NET_IP_ALIGN

			 * if this is a 5701 card running in PCI-X mode

			 * [see tg3_get_invariants()]

			 */

		) {

			int skb_size;
@@ -4256,11 +4261,12 @@ static int tg3_rx(struct tg3 *tp, int budget) 
			tg3_recycle_rx(tp, opaque_key,

				       desc_idx, *post_ptr);



			copy_skb = netdev_alloc_skb(tp->dev, len + 2);

			copy_skb = netdev_alloc_skb(tp->dev,

						    len + TG3_RAW_IP_ALIGN);

			if (copy_skb == NULL)

				goto drop_it_no_recycle;



			skb_reserve(copy_skb, 2);

			skb_reserve(copy_skb, TG3_RAW_IP_ALIGN);

			skb_put(copy_skb, len);

			pci_dma_sync_single_for_cpu(tp->pdev, dma_addr, len, PCI_DMA_FROMDEVICE);

			skb_copy_from_linear_data(skb, copy_skb->data, len);
@@ -12614,7 +12620,7 @@ static int __devinit tg3_get_invariants(struct tg3 *tp) 
	else

		tp->tg3_flags &= ~TG3_FLAG_POLL_SERDES;



	tp->rx_offset = 2;

	tp->rx_offset = NET_IP_ALIGN;

	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5701 &&

	    (tp->tg3_flags & TG3_FLAG_PCIX_MODE) != 0)

		tp->rx_offset = 0;

CRA Git | Maintained and supported by SUSTech CRA and CCSE