From 0b4cec8c2e872a6bc9146a001d7532f31023aed5 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 15 Jan 2014 08:58:06 -0800 Subject: [PATCH] net: Check skb->rxhash in gro_receive When initializing a gro_list for a packet, first check the rxhash of the incoming skb against that of the skb's in the list. This should be a very strong inidicator of whether the flow is going to be matched, and potentially allows a lot of other checks to be short circuited. Use skb_hash_raw so that we don't force the hash to be calculated. Tested by running netperf 200 TCP_STREAMs between two machines with GRO, HW rxhash, and 1G. Saw no performance degration, slight reduction of time in dev_gro_receive. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- net/core/dev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 995755733997..b2c1869b04e3 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3821,10 +3821,18 @@ static void gro_list_prepare(struct napi_struct *napi, struct sk_buff *skb) { struct sk_buff *p; unsigned int maclen = skb->dev->hard_header_len; + u32 hash = skb_get_hash_raw(skb); for (p = napi->gro_list; p; p = p->next) { unsigned long diffs; + NAPI_GRO_CB(p)->flush = 0; + + if (hash != skb_get_hash_raw(p)) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; diffs |= p->vlan_tci ^ skb->vlan_tci; if (maclen == ETH_HLEN) @@ -3835,7 +3843,6 @@ static void gro_list_prepare(struct napi_struct *napi, struct sk_buff *skb) skb_gro_mac_header(skb), maclen); NAPI_GRO_CB(p)->same_flow = !diffs; - NAPI_GRO_CB(p)->flush = 0; } } -- GitLab