Commit f38b782d authored by Sasha Neftin's avatar Sasha Neftin Committed by Jeff Kirsher
Browse files

igc: Add support for TSO 



TCP segmentation offload allows a device to segment a single frame
into multiple frames with a data payload size specified in socket buffer.
As a result we can now send data approximately up to seven percents fast
than was previously possible on my system.

Signed-off-by: default avatarSasha Neftin <sasha.neftin@intel.com>
Tested-by: default avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 0e7d4b93

drivers/net/ethernet/intel/igc/igc_defines.h

+4 −0
Original line number Diff line number Diff line
@@ -282,6 +282,10 @@ 
#define IGC_TXD_STAT_TC		0x00000004 /* Tx Underrun */

#define IGC_TXD_EXTCMD_TSTAMP	0x00000010 /* IEEE1588 Timestamp packet */



/* IPSec Encrypt Enable */

#define IGC_ADVTXD_L4LEN_SHIFT	8  /* Adv ctxt L4LEN shift */

#define IGC_ADVTXD_MSS_SHIFT	16 /* Adv ctxt MSS shift */



/* Transmit Control */

#define IGC_TCTL_EN		0x00000002 /* enable Tx */

#define IGC_TCTL_PSP		0x00000008 /* pad short packets */

drivers/net/ethernet/intel/igc/igc_main.c

+112 −1
Original line number Diff line number Diff line
@@ -1000,6 +1000,10 @@ static u32 igc_tx_cmd_type(struct sk_buff *skb, u32 tx_flags) 
		       IGC_ADVTXD_DCMD_DEXT |

		       IGC_ADVTXD_DCMD_IFCS;



	/* set segmentation bits for TSO */

	cmd_type |= IGC_SET_FLAG(tx_flags, IGC_TX_FLAGS_TSO,

				 (IGC_ADVTXD_DCMD_TSE));



	/* set timestamp bit if present */

	cmd_type |= IGC_SET_FLAG(tx_flags, IGC_TX_FLAGS_TSTAMP,

				 (IGC_ADVTXD_MAC_TSTAMP));
@@ -1171,6 +1175,100 @@ dma_error: 
	return -1;

}



static int igc_tso(struct igc_ring *tx_ring,

		   struct igc_tx_buffer *first,

		   u8 *hdr_len)

{

	u32 vlan_macip_lens, type_tucmd, mss_l4len_idx;

	struct sk_buff *skb = first->skb;

	union {

		struct iphdr *v4;

		struct ipv6hdr *v6;

		unsigned char *hdr;

	} ip;

	union {

		struct tcphdr *tcp;

		struct udphdr *udp;

		unsigned char *hdr;

	} l4;

	u32 paylen, l4_offset;

	int err;



	if (skb->ip_summed != CHECKSUM_PARTIAL)

		return 0;



	if (!skb_is_gso(skb))

		return 0;



	err = skb_cow_head(skb, 0);

	if (err < 0)

		return err;



	ip.hdr = skb_network_header(skb);

	l4.hdr = skb_checksum_start(skb);



	/* ADV DTYP TUCMD MKRLOC/ISCSIHEDLEN */

	type_tucmd = IGC_ADVTXD_TUCMD_L4T_TCP;



	/* initialize outer IP header fields */

	if (ip.v4->version == 4) {

		unsigned char *csum_start = skb_checksum_start(skb);

		unsigned char *trans_start = ip.hdr + (ip.v4->ihl * 4);



		/* IP header will have to cancel out any data that

		 * is not a part of the outer IP header

		 */

		ip.v4->check = csum_fold(csum_partial(trans_start,

						      csum_start - trans_start,

						      0));

		type_tucmd |= IGC_ADVTXD_TUCMD_IPV4;



		ip.v4->tot_len = 0;

		first->tx_flags |= IGC_TX_FLAGS_TSO |

				   IGC_TX_FLAGS_CSUM |

				   IGC_TX_FLAGS_IPV4;

	} else {

		ip.v6->payload_len = 0;

		first->tx_flags |= IGC_TX_FLAGS_TSO |

				   IGC_TX_FLAGS_CSUM;

	}



	/* determine offset of inner transport header */

	l4_offset = l4.hdr - skb->data;



	/* remove payload length from inner checksum */

	paylen = skb->len - l4_offset;

	if (type_tucmd & IGC_ADVTXD_TUCMD_L4T_TCP) {

		/* compute length of segmentation header */

		*hdr_len = (l4.tcp->doff * 4) + l4_offset;

		csum_replace_by_diff(&l4.tcp->check,

				     (__force __wsum)htonl(paylen));

	} else {

		/* compute length of segmentation header */

		*hdr_len = sizeof(*l4.udp) + l4_offset;

		csum_replace_by_diff(&l4.udp->check,

				     (__force __wsum)htonl(paylen));

	}



	/* update gso size and bytecount with header size */

	first->gso_segs = skb_shinfo(skb)->gso_segs;

	first->bytecount += (first->gso_segs - 1) * *hdr_len;



	/* MSS L4LEN IDX */

	mss_l4len_idx = (*hdr_len - l4_offset) << IGC_ADVTXD_L4LEN_SHIFT;

	mss_l4len_idx |= skb_shinfo(skb)->gso_size << IGC_ADVTXD_MSS_SHIFT;



	/* VLAN MACLEN IPLEN */

	vlan_macip_lens = l4.hdr - ip.hdr;

	vlan_macip_lens |= (ip.hdr - skb->data) << IGC_ADVTXD_MACLEN_SHIFT;

	vlan_macip_lens |= first->tx_flags & IGC_TX_FLAGS_VLAN_MASK;



	igc_tx_ctxtdesc(tx_ring, first, vlan_macip_lens,

			type_tucmd, mss_l4len_idx);



	return 1;

}



static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb,

				       struct igc_ring *tx_ring)

{
@@ -1180,6 +1278,7 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, 
	u32 tx_flags = 0;

	unsigned short f;

	u8 hdr_len = 0;

	int tso = 0;



	/* need: 1 descriptor per page * PAGE_SIZE/IGC_MAX_DATA_PER_TXD,

	 *	+ 1 desc for skb_headlen/IGC_MAX_DATA_PER_TXD,
@@ -1226,10 +1325,20 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, 
	first->tx_flags = tx_flags;

	first->protocol = protocol;



	tso = igc_tso(tx_ring, first, &hdr_len);

	if (tso < 0)

		goto out_drop;

	else if (!tso)

		igc_tx_csum(tx_ring, first);



	igc_tx_map(tx_ring, first, hdr_len);



	return NETDEV_TX_OK;



out_drop:

	dev_kfree_skb_any(first->skb);

	first->skb = NULL;



	return NETDEV_TX_OK;

}
@@ -4589,6 +4698,8 @@ static int igc_probe(struct pci_dev *pdev, 


	/* Add supported features to the features list*/

	netdev->features |= NETIF_F_SG;

	netdev->features |= NETIF_F_TSO;

	netdev->features |= NETIF_F_TSO6;

	netdev->features |= NETIF_F_RXCSUM;

	netdev->features |= NETIF_F_HW_CSUM;

	netdev->features |= NETIF_F_SCTP_CRC;

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