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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-19 21:56:38 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-04-20 01:18:06 -0700 |
| commit | b249dcb82d327e419d3cb45773b146ebb5faf419 (patch) | |
| tree | 3424eac7e208c03a49ad182685f1ba3c836628b8 | |
| parent | rps: cleanups (diff) | |
| download | linux-dev-b249dcb82d327e419d3cb45773b146ebb5faf419.tar.xz linux-dev-b249dcb82d327e419d3cb45773b146ebb5faf419.zip | |
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>
| -rw-r--r-- | net/core/dev.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 7f5755b0a57c..0d78e0454a6d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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; |