From aa6320d336971171df1d13c1c284facf10804881 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 8 Feb 2009 18:00:40 +0000 Subject: [PATCH] gro: Optimise TCP packet reception gro: Optimise TCP packet reception As this function can be called more than half a million times for 10GbE, it's important to optimise it as much as we can. This patch uses bit ops to logical ops, as well as open coding memcmp to exploit alignment properties. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 73266b79c19a..90b2f3c192ff 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2478,9 +2478,9 @@ struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) struct tcphdr *th2; unsigned int thlen; unsigned int flags; - unsigned int total; unsigned int mss = 1; int flush = 1; + int i; th = skb_gro_header(skb, sizeof(*th)); if (unlikely(!th)) @@ -2504,7 +2504,7 @@ struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) th2 = tcp_hdr(p); - if (th->source != th2->source || th->dest != th2->dest) { + if ((th->source ^ th2->source) | (th->dest ^ th2->dest)) { NAPI_GRO_CB(p)->same_flow = 0; continue; } @@ -2519,14 +2519,15 @@ found: flush |= flags & TCP_FLAG_CWR; flush |= (flags ^ tcp_flag_word(th2)) & ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH); - flush |= th->ack_seq != th2->ack_seq || th->window != th2->window; - flush |= memcmp(th + 1, th2 + 1, thlen - sizeof(*th)); + flush |= (th->ack_seq ^ th2->ack_seq) | (th->window ^ th2->window); + for (i = sizeof(*th); !flush && i < thlen; i += 4) + flush |= *(u32 *)((u8 *)th + i) ^ + *(u32 *)((u8 *)th2 + i); - total = skb_gro_len(p); mss = skb_shinfo(p)->gso_size; - flush |= skb_gro_len(skb) > mss || !skb_gro_len(skb); - flush |= ntohl(th2->seq) + total != ntohl(th->seq); + flush |= (skb_gro_len(skb) > mss) | !skb_gro_len(skb); + flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); if (flush || skb_gro_receive(head, skb)) { mss = 1; -- 2.20.1