Merge branch 'ipv6_dev_get_saddr-rcu'
Eric Dumazet says:
====================
ipv6: ipv6_dev_get_saddr() rcu works
Sending IPv6 udp packets on non connected sockets is quite slow,
because ipv6_dev_get_saddr() is still using an rwlock and silly
references games on ifa.
Tested:
$ ./super_netperf 16 -H 4444::555:0786 -l 2000 -t UDP_STREAM -- -m 100 &
[1] 12527
Performance is boosted from 2.02 Mpps to 4.28 Mpps
Kernel profile before patches :
22.62% [kernel] [k] _raw_read_lock_bh
7.04% [kernel] [k] refcount_sub_and_test
6.56% [kernel] [k] ipv6_get_saddr_eval
5.67% [kernel] [k] _raw_read_unlock_bh
5.34% [kernel] [k] __ipv6_dev_get_saddr
4.95% [kernel] [k] refcount_inc_not_zero
4.03% [kernel] [k] __ip6addrlbl_match
3.70% [kernel] [k] _raw_spin_lock
3.44% [kernel] [k] ipv6_dev_get_saddr
3.24% [kernel] [k] ip6_pol_route
3.06% [kernel] [k] refcount_add_not_zero
2.30% [kernel] [k] __local_bh_enable_ip
1.81% [kernel] [k] mlx4_en_xmit
1.20% [kernel] [k] __ip6_append_data
1.12% [kernel] [k] __ip6_make_skb
1.11% [kernel] [k] __dev_queue_xmit
1.06% [kernel] [k] l3mdev_master_ifindex_rcu
Kernel profile after patches :
11.36% [kernel] [k] ip6_pol_route
7.65% [kernel] [k] _raw_spin_lock
7.16% [kernel] [k] __ipv6_dev_get_saddr
6.49% [kernel] [k] ipv6_get_saddr_eval
6.04% [kernel] [k] refcount_add_not_zero
3.34% [kernel] [k] __ip6addrlbl_match
2.62% [kernel] [k] __dev_queue_xmit
2.37% [kernel] [k] mlx4_en_xmit
2.26% [kernel] [k] dst_release
1.89% [kernel] [k] __ip6_make_skb
1.87% [kernel] [k] __ip6_append_data
1.86% [kernel] [k] udpv6_sendmsg
1.86% [kernel] [k] ip6t_do_table
1.64% [kernel] [k] ipv6_dev_get_saddr
1.64% [kernel] [k] find_match
1.51% [kernel] [k] l3mdev_master_ifindex_rcu
1.24% [kernel] [k] ipv6_addr_label
====================
Signed-off-by: David S. Miller <davem@davemloft.net>