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Message-Id: <1328918904-11511-3-git-send-email-jeffrey.t.kirsher@intel.com>
Date: Fri, 10 Feb 2012 16:08:19 -0800
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Alexander Duyck <alexander.h.duyck@...el.com>,
netdev@...r.kernel.org, gospo@...hat.com, sassmann@...hat.com,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 2/7] ixgbe: Address fact that RSC was not setting GSO size for incoming frames
From: Alexander Duyck <alexander.h.duyck@...el.com>
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 <alexander.h.duyck@...el.com>
Tested-by: Stephen Ko <stephen.s.ko@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 130 ++++++++++++++++++++++++-
1 files 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 18e474c..762f3377 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)) {
--
1.7.7.6
--
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