From e68b6e50fa359cc5aad4d2f8ac2bdbc1a8f4fd59 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 16 Nov 2016 09:10:42 -0800 Subject: [PATCH] udp: enable busy polling for all sockets UDP busy polling is restricted to connected UDP sockets. This is because sk_busy_loop() only takes care of one NAPI context. There are cases where it could be extended. 1) Some hosts receive traffic on a single NIC, with one RX queue. 2) Some applications use SO_REUSEPORT and associated BPF filter to split the incoming traffic on one UDP socket per RX queue/thread/cpu 3) Some UDP sockets are used to send/receive traffic for one flow, but they do not bother with connect() This patch records the napi_id of first received skb, giving more reach to busy polling. Tested: lpaa23:~# echo 70 >/proc/sys/net/core/busy_read lpaa24:~# echo 70 >/proc/sys/net/core/busy_read lpaa23:~# for f in `seq 1 10`; do ./super_netperf 1 -H lpaa24 -t UDP_RR -l 5; done Before patch : 27867 28870 37324 41060 41215 36764 36838 44455 41282 43843 After patch : 73920 73213 70147 74845 71697 68315 68028 75219 70082 73707 Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Signed-off-by: David S. Miller --- include/net/busy_poll.h | 28 +++++++++++++++++++--------- net/ipv4/udp.c | 2 ++ net/ipv6/udp.c | 2 ++ 3 files changed, 23 insertions(+), 9 deletions(-) diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index 965e52b9b5a3..d73b849e29a6 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -80,11 +80,6 @@ static inline void skb_mark_napi_id(struct sk_buff *skb, skb->napi_id = napi->napi_id; } -/* used in the protocol hanlder to propagate the napi_id to the socket */ -static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb) -{ - sk->sk_napi_id = skb->napi_id; -} #else /* CONFIG_NET_RX_BUSY_POLL */ static inline unsigned long net_busy_loop_on(void) @@ -107,10 +102,6 @@ static inline void skb_mark_napi_id(struct sk_buff *skb, { } -static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb) -{ -} - static inline bool busy_loop_timeout(unsigned long end_time) { return true; @@ -122,4 +113,23 @@ static inline bool sk_busy_loop(struct sock *sk, int nonblock) } #endif /* CONFIG_NET_RX_BUSY_POLL */ + +/* used in the protocol hanlder to propagate the napi_id to the socket */ +static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + sk->sk_napi_id = skb->napi_id; +#endif +} + +/* variant used for unconnected sockets */ +static inline void sk_mark_napi_id_once(struct sock *sk, + const struct sk_buff *skb) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + if (!sk->sk_napi_id) + sk->sk_napi_id = skb->napi_id; +#endif +} + #endif /* _LINUX_NET_BUSY_POLL_H */ diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 9ae7c63a8b13..e1fc0116e8d5 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1569,6 +1569,8 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) sock_rps_save_rxhash(sk, skb); sk_mark_napi_id(sk, skb); sk_incoming_cpu_update(sk); + } else { + sk_mark_napi_id_once(sk, skb); } rc = __udp_enqueue_schedule_skb(sk, skb); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 86a8cacd333b..4f99417d9b40 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -519,6 +519,8 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) sock_rps_save_rxhash(sk, skb); sk_mark_napi_id(sk, skb); sk_incoming_cpu_update(sk); + } else { + sk_mark_napi_id_once(sk, skb); } rc = __udp_enqueue_schedule_skb(sk, skb); -- 2.30.2