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| author | Eric Dumazet <edumazet@google.com> | 2015-10-09 04:33:22 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-10-13 04:28:22 +0200 |
| commit | 8e5eb54d303b7cb1174977ca79030e135728c95e (patch) | |
| tree | 9aebc1d9e60ccbb559dac5d0d8d11f41b95df3c2 /include/net/request_sock.h | |
| parent | net: SO_INCOMING_CPU setsockopt() support (diff) | |
| download | linux-8e5eb54d303b7cb1174977ca79030e135728c95e.tar.xz linux-8e5eb54d303b7cb1174977ca79030e135728c95e.zip | |
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/request_sock.h')
| -rw-r--r-- | include/net/request_sock.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/request_sock.h b/include/net/request_sock.h index 95ab5d7aab96..6b818b77d5e5 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -50,9 +50,9 @@ struct request_sock { struct sock_common __req_common; #define rsk_refcnt __req_common.skc_refcnt #define rsk_hash __req_common.skc_hash +#define rsk_listener __req_common.skc_listener struct request_sock *dl_next; - struct sock *rsk_listener; u16 mss; u8 num_retrans; /* number of retransmits */ u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */ |