tcp: do not lock listener to process SYN packets
Everything should now be ready to finally allow SYN
packets processing without holding listener lock.
Tested:
3.5 Mpps SYNFLOOD. Plenty of cpu cycles available.
Next bottleneck is the refcount taken on listener,
that could be avoided if we remove SLAB_DESTROY_BY_RCU
strict semantic for listeners, and use regular RCU.
13.18% [kernel] [k] __inet_lookup_listener
9.61% [kernel] [k] tcp_conn_request
8.16% [kernel] [k] sha_transform
5.30% [kernel] [k] inet_reqsk_alloc
4.22% [kernel] [k] sock_put
3.74% [kernel] [k] tcp_make_synack
2.88% [kernel] [k] ipt_do_table
2.56% [kernel] [k] memcpy_erms
2.53% [kernel] [k] sock_wfree
2.40% [kernel] [k] tcp_v4_rcv
2.08% [kernel] [k] fib_table_lookup
1.84% [kernel] [k] tcp_openreq_init_rwin
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2 files changed