From: Changli Gao <xiaosuo@gmail.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: Tom Herbert <therbert@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
netdev@vger.kernel.org, Changli Gao <xiaosuo@gmail.com>
Subject: [PATCH v2] rps: optimize rps_get_cpu()
Date: Tue, 20 Apr 2010 22:02:40 +0800 [thread overview]
Message-ID: <1271772160-28177-1-git-send-email-xiaosuo@gmail.com> (raw)
optimize rps_get_cpu().
don't initialize ports when we can get the ports. one memory access for ports
than two. use ihl in bytes to eliminate later multiplyings.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
net/core/dev.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index b31d5d6..55ecfa9 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2225,7 +2225,11 @@ 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);
@@ -2256,7 +2260,7 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
ip_proto = ip->protocol;
addr1 = (__force u32) ip->saddr;
addr2 = (__force u32) ip->daddr;
- ihl = ip->ihl;
+ ihl = ip->ihl << 2;
break;
case __constant_htons(ETH_P_IPV6):
if (!pskb_may_pull(skb, sizeof(*ip6)))
@@ -2266,12 +2270,11 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
ip_proto = ip6->nexthdr;
addr1 = (__force u32) ip6->saddr.s6_addr32[3];
addr2 = (__force u32) ip6->daddr.s6_addr32[3];
- ihl = (40 >> 2);
+ ihl = 40;
break;
default:
goto done;
}
- ports = 0;
switch (ip_proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
@@ -2280,26 +2283,21 @@ 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)) {
- __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;
+ if (pskb_may_pull(skb, ihl + 4)) {
+ ports.v32 = * (__force u32 *) (skb->data + ihl);
+ if (ports.v16[0] < ports.v16[1])
+ swap(ports.v16[0], ports.v16[1]);
+ break;
}
- 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;
next reply other threads:[~2010-04-20 14:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-20 14:02 Changli Gao [this message]
2010-04-22 5:40 ` [PATCH v2] rps: optimize rps_get_cpu() David Miller
2010-04-22 6:10 ` Changli Gao
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