Commit 4b943fae authored Jun 22, 2017 by Paolo Abeni Committed by David S. Miller Jun 22, 2017

udp/v6: prefetch rmem_alloc in udp6_queue_rcv_skb()



very similar to commit dd99e425 ("udp: prefetch
rmem_alloc in udp_queue_rcv_skb()"), this allows saving a cache
miss when the BH is bottle-neck for UDP over ipv6 packet
processing, e.g. for small packets when a single RX NIC ingress
queue is in use.

Performances under flood when multiple NIC RX queues used are
unaffected, but when a single NIC rx queue is in use, this
gives ~8% performance improvement.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent ea9fc3c5

net/ipv6/udp.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -630,6 +630,7 @@ static int udpv6_queue_rcv_skb(struct sock sk, struct sk_buff skb)
		}
		}

		prefetch(&sk->sk_rmem_alloc);
		if (rcu_access_pointer(sk->sk_filter) &&
		udp_lib_checksum_complete(skb))
		goto csum_error;

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