tcp: remove false sharing in tcp_rcv_state_process()
authorEric Dumazet <edumazet@google.com>
Thu, 14 Apr 2016 05:05:40 +0000 (22:05 -0700)
committerDavid S. Miller <davem@davemloft.net>
Fri, 15 Apr 2016 20:45:44 +0000 (16:45 -0400)
commit8804b2722dc5d6f9b7ba0a9e812eae9ee5ce95bc
treefd1010fca7c152ca547f02d80a02dc9d1b9d7b20
parentb3d051477cf94e9d71d6acadb8a90de15237b9c1
tcp: remove false sharing in tcp_rcv_state_process()

Last known hot point during SYNFLOOD attack is the clearing
of rx_opt.saw_tstamp in tcp_rcv_state_process()

It is not needed for a listener, so we move it where it matters.

Performance while a SYNFLOOD hits a single listener socket
went from 5 Mpps to 6 Mpps on my test server (24 cores, 8 NIC RX queues)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp_input.c