From c6865cb3cc6f3c2857fa4c6f5fda2945d70b1e84 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Sun, 14 Aug 2011 19:46:29 +0000 Subject: [PATCH] rps: Inspect GRE encapsulated packets to get flow hash Crack open GRE packets in __skb_get_rxhash to compute 4-tuple hash on in encapsulated packet. Note that this is used only when the __skb_get_rxhash is taken, in particular only when the device does not compute provide the rxhash (ie. feature is disabled). This was tested by creating a single GRE tunnel between two 16 core AMD machines. 200 netperf TCP_RR streams were ran with 1 byte request and response size. Without patch: 157497 tps, 50/90/99% latencies 1250/1292/1364 usecs With patch: 325896 tps, 50/90/99% latencies 603/848/1169 Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- net/core/dev.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 4bee9a9aeef6..a8d91a5dd909 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2570,6 +2570,28 @@ void __skb_get_rxhash(struct sk_buff *skb) } switch (ip_proto) { + case IPPROTO_GRE: + if (pskb_may_pull(skb, nhoff + 16)) { + u8 *h = skb->data + nhoff; + __be16 flags = *(__be16 *)h; + + /* + * Only look inside GRE if version zero and no + * routing + */ + if (!(flags & (GRE_VERSION|GRE_ROUTING))) { + proto = *(__be16 *)(h + 2); + nhoff += 4; + if (flags & GRE_CSUM) + nhoff += 4; + if (flags & GRE_KEY) + nhoff += 4; + if (flags & GRE_SEQ) + nhoff += 4; + goto again; + } + } + break; default: break; }