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Commit 8c52d509 authored by Changli Gao's avatar Changli Gao Committed by David S. Miller
Browse files

rps: optimize rps_get_cpu() 



optimize rps_get_cpu().

don't initialize ports when we can get the ports. one memory access
for ports than two.

Signed-off-by: default avatarChangli Gao <xiaosuo@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bf73130d

net/core/dev.c

+11 −13
Original line number Diff line number Diff line
@@ -2229,7 +2229,11 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	int cpu = -1;

	u8 ip_proto;

	u16 tcpu;

	u32 addr1, addr2, ports, ihl;

	u32 addr1, addr2, ihl;

	union {

		u32 v32;

		u16 v16[2];

	} ports;



	if (skb_rx_queue_recorded(skb)) {

		u16 index = skb_get_rx_queue(skb);
@@ -2275,7 +2279,6 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	default:

		goto done;

	}

	ports = 0;

	switch (ip_proto) {

	case IPPROTO_TCP:

	case IPPROTO_UDP:
@@ -2285,25 +2288,20 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	case IPPROTO_SCTP:

	case IPPROTO_UDPLITE:

		if (pskb_may_pull(skb, (ihl * 4) + 4)) {

			__be16 *hports = (__be16 *) (skb->data + (ihl * 4));

			u32 sport, dport;



			sport = (__force u16) hports[0];

			dport = (__force u16) hports[1];

			if (dport < sport)

				swap(sport, dport);

			ports = (sport << 16) + dport;

		}

			ports.v32 = * (__force u32 *) (skb->data + (ihl * 4));

			if (ports.v16[1] < ports.v16[0])

				swap(ports.v16[0], ports.v16[1]);

			break;



		}

	default:

		ports.v32 = 0;

		break;

	}



	/* get a consistent hash (same value on both flow directions) */

	if (addr2 < addr1)

		swap(addr1, addr2);

	skb->rxhash = jhash_3words(addr1, addr2, ports, hashrnd);

	skb->rxhash = jhash_3words(addr1, addr2, ports.v32, hashrnd);

	if (!skb->rxhash)

		skb->rxhash = 1;