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rps: optimize rps_get_cpu()

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optimize rps_get_cpu().

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

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Changli Gao 2010-04-24 22:50:10 -07:00 committed by David S. Miller
parent bf73130d7f
commit 8c52d509e8
1 changed files with 11 additions and 13 deletions
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24
net/core/dev.c
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@ -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;