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authorEric Dumazet <edumazet@google.com>2015-10-08 19:33:22 -0700
committerDavid S. Miller <davem@davemloft.net>2015-10-12 19:28:22 -0700
commit8e5eb54d303b7cb1174977ca79030e135728c95e (patch)
tree9aebc1d9e60ccbb559dac5d0d8d11f41b95df3c2 /include/net/inet_timewait_sock.h
parentnet: SO_INCOMING_CPU setsockopt() support (diff)
downloadlinux-dev-8e5eb54d303b7cb1174977ca79030e135728c95e.tar.xz
linux-dev-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/inet_timewait_sock.h')
-rw-r--r--include/net/inet_timewait_sock.h2
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