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| author | Eric Dumazet <edumazet@google.com> | 2015-10-08 19:33:22 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-10-12 19:28:22 -0700 |
| commit | 8e5eb54d303b7cb1174977ca79030e135728c95e (patch) | |
| tree | 9aebc1d9e60ccbb559dac5d0d8d11f41b95df3c2 /include/net/inet_timewait_sock.h | |
| parent | 70da268b569d32a9fddeea85dc18043de9d89f89 (diff) | |
| download | linux-8e5eb54d303b7cb1174977ca79030e135728c95e.tar.bz2 | |
net: align sk_refcnt on 128 bytes boundary
sk->sk_refcnt is dirtied for every TCP/UDP incoming packet.
This is a performance issue if multiple cpus hit a common socket,
or multiple sockets are chained due to SO_REUSEPORT.
By moving sk_refcnt 8 bytes further, first 128 bytes of sockets
are mostly read. As they contain the lookup keys, this has
a considerable performance impact, as cpus can cache them.
These 8 bytes are not wasted, we use them as a place holder
for various fields, depending on the socket type.
Tested:
SYN flood hitting a 16 RX queues NIC.
TCP listener using 16 sockets and SO_REUSEPORT
and SO_INCOMING_CPU for proper siloing.
Could process 6.0 Mpps SYN instead of 4.2 Mpps
Kernel profile looked like :
11.68% [kernel] [k] sha_transform
6.51% [kernel] [k] __inet_lookup_listener
5.07% [kernel] [k] __inet_lookup_established
4.15% [kernel] [k] memcpy_erms
3.46% [kernel] [k] ipt_do_table
2.74% [kernel] [k] fib_table_lookup
2.54% [kernel] [k] tcp_make_synack
2.34% [kernel] [k] tcp_conn_request
2.05% [kernel] [k] __netif_receive_skb_core
2.03% [kernel] [k] kmem_cache_alloc
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/inet_timewait_sock.h')
| -rw-r--r-- | include/net/inet_timewait_sock.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h index 186f3a1e1b1f..e581fc69129d 100644 --- a/include/net/inet_timewait_sock.h +++ b/include/net/inet_timewait_sock.h @@ -70,6 +70,7 @@ struct inet_timewait_sock { #define tw_dport __tw_common.skc_dport #define tw_num __tw_common.skc_num #define tw_cookie __tw_common.skc_cookie +#define tw_dr __tw_common.skc_tw_dr int tw_timeout; volatile unsigned char tw_substate; @@ -88,7 +89,6 @@ struct inet_timewait_sock { kmemcheck_bitfield_end(flags); struct timer_list tw_timer; struct inet_bind_bucket *tw_tb; - struct inet_timewait_death_row *tw_dr; }; #define tw_tclass tw_tos |