From 1d2024f61ec14bdb0c57a97a3fe73685abc2d198 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Tue, 31 Jan 2012 02:59:29 +0000 Subject: [PATCH] ixgbe: Address fact that RSC was not setting GSO size for incoming frames This patch is meant to address the fact that RSC has not been setting the gso_size value on the skb. As a result performance on lossy TCP connections was negatively impacted. This change resolves the issue by setting gso_size to the average size for incoming packets. Signed-off-by: Alexander Duyck Tested-by: Stephen Ko Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 130 +++++++++++++++++- 1 file changed, 125 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 18e474c25e61..762f33777a7f 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -1276,6 +1276,104 @@ static inline bool ixgbe_close_active_frag_list(struct sk_buff *head) return true; } +/** + * ixgbe_get_headlen - determine size of header for RSC/LRO/GRO/FCOE + * @data: pointer to the start of the headers + * @max_len: total length of section to find headers in + * + * This function is meant to determine the length of headers that will + * be recognized by hardware for LRO, GRO, and RSC offloads. The main + * motivation of doing this is to only perform one pull for IPv4 TCP + * packets so that we can do basic things like calculating the gso_size + * based on the average data per packet. + **/ +static unsigned int ixgbe_get_headlen(unsigned char *data, + unsigned int max_len) +{ + union { + unsigned char *network; + /* l2 headers */ + struct ethhdr *eth; + struct vlan_hdr *vlan; + /* l3 headers */ + struct iphdr *ipv4; + } hdr; + __be16 protocol; + u8 nexthdr = 0; /* default to not TCP */ + u8 hlen; + + /* this should never happen, but better safe than sorry */ + if (max_len < ETH_HLEN) + return max_len; + + /* initialize network frame pointer */ + hdr.network = data; + + /* set first protocol and move network header forward */ + protocol = hdr.eth->h_proto; + hdr.network += ETH_HLEN; + + /* handle any vlan tag if present */ + if (protocol == __constant_htons(ETH_P_8021Q)) { + if ((hdr.network - data) > (max_len - VLAN_HLEN)) + return max_len; + + protocol = hdr.vlan->h_vlan_encapsulated_proto; + hdr.network += VLAN_HLEN; + } + + /* handle L3 protocols */ + if (protocol == __constant_htons(ETH_P_IP)) { + if ((hdr.network - data) > (max_len - sizeof(struct iphdr))) + return max_len; + + /* access ihl as a u8 to avoid unaligned access on ia64 */ + hlen = (hdr.network[0] & 0x0F) << 2; + + /* verify hlen meets minimum size requirements */ + if (hlen < sizeof(struct iphdr)) + return hdr.network - data; + + /* record next protocol */ + nexthdr = hdr.ipv4->protocol; + hdr.network += hlen; +#ifdef CONFIG_FCOE + } else if (protocol == __constant_htons(ETH_P_FCOE)) { + if ((hdr.network - data) > (max_len - FCOE_HEADER_LEN)) + return max_len; + hdr.network += FCOE_HEADER_LEN; +#endif + } else { + return hdr.network - data; + } + + /* finally sort out TCP */ + if (nexthdr == IPPROTO_TCP) { + if ((hdr.network - data) > (max_len - sizeof(struct tcphdr))) + return max_len; + + /* access doff as a u8 to avoid unaligned access on ia64 */ + hlen = (hdr.network[12] & 0xF0) >> 2; + + /* verify hlen meets minimum size requirements */ + if (hlen < sizeof(struct tcphdr)) + return hdr.network - data; + + hdr.network += hlen; + } + + /* + * If everything has gone correctly hdr.network should be the + * data section of the packet and will be the end of the header. + * If not then it probably represents the end of the last recognized + * header. + */ + if ((hdr.network - data) < max_len) + return hdr.network - data; + else + return max_len; +} + static void ixgbe_get_rsc_cnt(struct ixgbe_ring *rx_ring, union ixgbe_adv_rx_desc *rx_desc, struct sk_buff *skb) @@ -1299,6 +1397,32 @@ static void ixgbe_get_rsc_cnt(struct ixgbe_ring *rx_ring, IXGBE_CB(skb)->append_cnt += rsc_cnt - 1; } +static void ixgbe_set_rsc_gso_size(struct ixgbe_ring *ring, + struct sk_buff *skb) +{ + u16 hdr_len = ixgbe_get_headlen(skb->data, skb_headlen(skb)); + + /* set gso_size to avoid messing up TCP MSS */ + skb_shinfo(skb)->gso_size = DIV_ROUND_UP((skb->len - hdr_len), + IXGBE_CB(skb)->append_cnt); +} + +static void ixgbe_update_rsc_stats(struct ixgbe_ring *rx_ring, + struct sk_buff *skb) +{ + /* if append_cnt is 0 then frame is not RSC */ + if (!IXGBE_CB(skb)->append_cnt) + return; + + rx_ring->rx_stats.rsc_count += IXGBE_CB(skb)->append_cnt; + rx_ring->rx_stats.rsc_flush++; + + ixgbe_set_rsc_gso_size(rx_ring, skb); + + /* gso_size is computed using append_cnt so always clear it last */ + IXGBE_CB(skb)->append_cnt = 0; +} + static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, struct ixgbe_ring *rx_ring, int budget) @@ -1437,11 +1561,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, goto next_desc; } - if (IXGBE_CB(skb)->append_cnt) { - rx_ring->rx_stats.rsc_count += - IXGBE_CB(skb)->append_cnt; - rx_ring->rx_stats.rsc_flush++; - } + ixgbe_update_rsc_stats(rx_ring, skb); /* ERR_MASK will only have valid bits if EOP set */ if (unlikely(staterr & IXGBE_RXDADV_ERR_FRAME_ERR_MASK)) { -- 2.20.1