From 6c7c98bad4883a4a8710c96b2b44de482865eb6e Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 30 Mar 2017 14:03:06 +0200 Subject: [PATCH] sock: avoid dirtying sk_stamp, if possible sock_recv_ts_and_drops() unconditionally set sk->sk_stamp for every packet, even if the SOCK_TIMESTAMP flag is not set in the related socket. If selinux is enabled, this cause a cache miss for every packet since sk->sk_stamp and sk->sk_security share the same cacheline. With this change sk_stamp is set only if the SOCK_TIMESTAMP flag is set, and is cleared for the first packet, so that the user perceived behavior is unchanged. This gives up to 5% speed-up under udp-flood with small packets. Signed-off-by: Paolo Abeni Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/sock.h | 5 ++++- net/core/sock.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index cb241a0e8434..8e53158a7d95 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2239,6 +2239,7 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb) void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk, struct sk_buff *skb); +#define SK_DEFAULT_STAMP (-1L * NSEC_PER_SEC) static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk, struct sk_buff *skb) { @@ -2249,8 +2250,10 @@ static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk, if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY) __sock_recv_ts_and_drops(msg, sk, skb); - else + else if (unlikely(sk->sk_flags & SOCK_TIMESTAMP)) sk->sk_stamp = skb->tstamp; + else if (unlikely(sk->sk_stamp == SK_DEFAULT_STAMP)) + sk->sk_stamp = 0; } void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags); diff --git a/net/core/sock.c b/net/core/sock.c index 1a58a9dc6888..392f9b6f96e2 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2613,7 +2613,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT; sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; - sk->sk_stamp = ktime_set(-1L, 0); + sk->sk_stamp = SK_DEFAULT_STAMP; #ifdef CONFIG_NET_RX_BUSY_POLL sk->sk_napi_id = 0; -- 2.20.1