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OpenCloudOS-Kernel
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rps: consistent rxhash 

In case we compute a software skb->rxhash, we can generate a consistent
hash : Its value will be the same in both flow directions.

This helps some workloads, like conntracking, since the same state needs
to be accessed in both directions.

tbench + RFS + this patch gives better results than tbench with default
kernel configuration (no RPS, no RFS)

Also fixed some sparse warnings.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-04-19 21:56:38 +00:00 committed by David S. Miller
parent e36fa2f7e9
commit b249dcb82d
1 changed files with 18 additions and 7 deletions
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25
net/core/dev.c
View File

@ -1974,7 +1974,7 @@ u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = skb->protocol;
hash = (__force u16) skb->protocol;
hash = jhash_1word(hash, hashrnd);
@ -2253,8 +2253,8 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
ip = (struct iphdr *) skb->data;
ip_proto = ip->protocol;
addr1 = ip->saddr;
addr2 = ip->daddr;
addr1 = (__force u32) ip->saddr;
addr2 = (__force u32) ip->daddr;
ihl = ip->ihl;
break;
case __constant_htons(ETH_P_IPV6):
@ -2263,8 +2263,8 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
ip6 = (struct ipv6hdr *) skb->data;
ip_proto = ip6->nexthdr;
addr1 = ip6->saddr.s6_addr32[3];
addr2 = ip6->daddr.s6_addr32[3];
addr1 = (__force u32) ip6->saddr.s6_addr32[3];
addr2 = (__force u32) ip6->daddr.s6_addr32[3];
ihl = (40 >> 2);
break;
default:
@ -2279,14 +2279,25 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
case IPPROTO_AH:
case IPPROTO_SCTP:
case IPPROTO_UDPLITE:
if (pskb_may_pull(skb, (ihl * 4) + 4))
ports = *((u32 *) (skb->data + (ihl * 4)));
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;
}
break;
default:
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);
if (!skb->rxhash)
skb->rxhash = 1;