| Message ID | 1444358004-26483-2-git-send-email-edumazet@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thu, Oct 8, 2015 at 7:33 PM, Eric Dumazet <edumazet@google.com> wrote: > SO_INCOMING_CPU as added in commit 2c8c56e15df3 was a getsockopt() command > to fetch incoming cpu handling a particular TCP flow after accept() > > This commits adds setsockopt() support and extends SO_REUSEPORT selection > logic : If a TCP listener or UDP socket has this option set, a packet is > delivered to this socket only if CPU handling the packet matches the specified > one. > > This allows to build very efficient TCP servers, using one listener per > RX queue, as the associated TCP listener should only accept flows handled > in softirq by the same cpu. > This provides optimal NUMA behavior and keep cpu caches hot. > > Note that __inet_lookup_listener() still has to iterate over the list of > all listeners. Following patch puts sk_refcnt in a different cache line > to let this iteration hit only shared and read mostly cache lines. > > Signed-off-by: Eric Dumazet <edumazet@google.com> > --- > include/net/sock.h | 10 ++++------ > net/core/sock.c | 5 +++++ > net/ipv4/inet_hashtables.c | 2 ++ > net/ipv4/udp.c | 6 +++++- > net/ipv6/inet6_hashtables.c | 2 ++ > net/ipv6/udp.c | 11 +++++++---- > 6 files changed, 25 insertions(+), 11 deletions(-) > > diff --git a/include/net/sock.h b/include/net/sock.h > index dfe2eb8e1132..08abffe32236 100644 > --- a/include/net/sock.h > +++ b/include/net/sock.h > @@ -150,6 +150,7 @@ typedef __u64 __bitwise __addrpair; > * @skc_node: main hash linkage for various protocol lookup tables > * @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol > * @skc_tx_queue_mapping: tx queue number for this connection > + * @skc_incoming_cpu: record/match cpu processing incoming packets > * @skc_refcnt: reference count > * > * This is the minimal network layer representation of sockets, the header > @@ -212,6 +213,8 @@ struct sock_common { > struct hlist_nulls_node skc_nulls_node; > }; > int skc_tx_queue_mapping; > + int skc_incoming_cpu; > + > atomic_t skc_refcnt; > /* private: */ > int skc_dontcopy_end[0]; > @@ -274,7 +277,6 @@ struct cg_proto; > * @sk_rcvtimeo: %SO_RCVTIMEO setting > * @sk_sndtimeo: %SO_SNDTIMEO setting > * @sk_rxhash: flow hash received from netif layer > - * @sk_incoming_cpu: record cpu processing incoming packets > * @sk_txhash: computed flow hash for use on transmit > * @sk_filter: socket filtering instructions > * @sk_timer: sock cleanup timer > @@ -331,6 +333,7 @@ struct sock { > #define sk_v6_daddr __sk_common.skc_v6_daddr > #define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr > #define sk_cookie __sk_common.skc_cookie > +#define sk_incoming_cpu __sk_common.skc_incoming_cpu > > socket_lock_t sk_lock; > struct sk_buff_head sk_receive_queue; > @@ -353,11 +356,6 @@ struct sock { > #ifdef CONFIG_RPS > __u32 sk_rxhash; > #endif > - u16 sk_incoming_cpu; > - /* 16bit hole > - * Warned : sk_incoming_cpu can be set from softirq, > - * Do not use this hole without fully understanding possible issues. > - */ > > __u32 sk_txhash; > #ifdef CONFIG_NET_RX_BUSY_POLL > diff --git a/net/core/sock.c b/net/core/sock.c > index 7dd1263e4c24..1071f9380250 100644 > --- a/net/core/sock.c > +++ b/net/core/sock.c > @@ -988,6 +988,10 @@ set_rcvbuf: > sk->sk_max_pacing_rate); > break; > > + case SO_INCOMING_CPU: > + sk->sk_incoming_cpu = val; > + break; > + > default: > ret = -ENOPROTOOPT; > break; > @@ -2353,6 +2357,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) > > sk->sk_max_pacing_rate = ~0U; > sk->sk_pacing_rate = ~0U; > + sk->sk_incoming_cpu = -1; > /* > * Before updating sk_refcnt, we must commit prior changes to memory > * (Documentation/RCU/rculist_nulls.txt for details) > diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c > index bed8886a4b6c..08643a3616af 100644 > --- a/net/ipv4/inet_hashtables.c > +++ b/net/ipv4/inet_hashtables.c > @@ -185,6 +185,8 @@ static inline int compute_score(struct sock *sk, struct net *net, > return -1; > score += 4; > } > + if (sk->sk_incoming_cpu == raw_smp_processor_id()) > + score++; > } > return score; > } > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index e1fc129099ea..24ec14f9825c 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -375,7 +375,8 @@ static inline int compute_score(struct sock *sk, struct net *net, > return -1; > score += 4; > } > - > + if (sk->sk_incoming_cpu == raw_smp_processor_id()) > + score++; > return score; > } > > @@ -419,6 +420,9 @@ static inline int compute_score2(struct sock *sk, struct net *net, > score += 4; > } > > + if (sk->sk_incoming_cpu == raw_smp_processor_id()) > + score++; > + > return score; > } > > diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c > index 6ac8dad0138a..21ace5a2bf7c 100644 > --- a/net/ipv6/inet6_hashtables.c > +++ b/net/ipv6/inet6_hashtables.c > @@ -114,6 +114,8 @@ static inline int compute_score(struct sock *sk, struct net *net, > return -1; > score++; > } > + if (sk->sk_incoming_cpu == raw_smp_processor_id()) > + score++; > } > return score; > } > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > index 0aba654f5b91..01bcb49619ee 100644 > --- a/net/ipv6/udp.c > +++ b/net/ipv6/udp.c > @@ -182,10 +182,12 @@ static inline int compute_score(struct sock *sk, struct net *net, > score++; > } > > + if (sk->sk_incoming_cpu == raw_smp_processor_id()) > + score++; > + > return score; > } > > -#define SCORE2_MAX (1 + 1 + 1) > static inline int compute_score2(struct sock *sk, struct net *net, > const struct in6_addr *saddr, __be16 sport, > const struct in6_addr *daddr, > @@ -223,6 +225,9 @@ static inline int compute_score2(struct sock *sk, struct net *net, > score++; > } > > + if (sk->sk_incoming_cpu == raw_smp_processor_id()) > + score++; > + > return score; > } > > @@ -251,8 +256,7 @@ begin: > hash = udp6_ehashfn(net, daddr, hnum, > saddr, sport); > matches = 1; > - } else if (score == SCORE2_MAX) > - goto exact_match; > + } Do we care about losing this optimization? It's not done in IPv4 but I can imagine that there is some arguments that address comparisons in IPv6 are more expensive hence this might make sense... > } else if (score == badness && reuseport) { > matches++; > if (reciprocal_scale(hash, matches) == 0) > @@ -269,7 +273,6 @@ begin: > goto begin; > > if (result) { > -exact_match: > if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2))) > result = NULL; > else if (unlikely(compute_score2(result, net, saddr, sport, > -- > 2.6.0.rc2.230.g3dd15c0 > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2015-10-08 at 20:40 -0700, Tom Herbert wrote: > Do we care about losing this optimization? It's not done in IPv4 but I > can imagine that there is some arguments that address comparisons in > IPv6 are more expensive hence this might make sense... I do not think we care. You removed the 'optimization' in IPv4 in commit ba418fa357a7b ("soreuseport: UDP/IPv4 implementation") back in 2013 and really no one noticed. The important factor here is the number of cache lines taken to traverse the list... -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/sock.h b/include/net/sock.h index dfe2eb8e1132..08abffe32236 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -150,6 +150,7 @@ typedef __u64 __bitwise __addrpair; * @skc_node: main hash linkage for various protocol lookup tables * @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol * @skc_tx_queue_mapping: tx queue number for this connection + * @skc_incoming_cpu: record/match cpu processing incoming packets * @skc_refcnt: reference count * * This is the minimal network layer representation of sockets, the header @@ -212,6 +213,8 @@ struct sock_common { struct hlist_nulls_node skc_nulls_node; }; int skc_tx_queue_mapping; + int skc_incoming_cpu; + atomic_t skc_refcnt; /* private: */ int skc_dontcopy_end[0]; @@ -274,7 +277,6 @@ struct cg_proto; * @sk_rcvtimeo: %SO_RCVTIMEO setting * @sk_sndtimeo: %SO_SNDTIMEO setting * @sk_rxhash: flow hash received from netif layer - * @sk_incoming_cpu: record cpu processing incoming packets * @sk_txhash: computed flow hash for use on transmit * @sk_filter: socket filtering instructions * @sk_timer: sock cleanup timer @@ -331,6 +333,7 @@ struct sock { #define sk_v6_daddr __sk_common.skc_v6_daddr #define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr #define sk_cookie __sk_common.skc_cookie +#define sk_incoming_cpu __sk_common.skc_incoming_cpu socket_lock_t sk_lock; struct sk_buff_head sk_receive_queue; @@ -353,11 +356,6 @@ struct sock { #ifdef CONFIG_RPS __u32 sk_rxhash; #endif - u16 sk_incoming_cpu; - /* 16bit hole - * Warned : sk_incoming_cpu can be set from softirq, - * Do not use this hole without fully understanding possible issues. - */ __u32 sk_txhash; #ifdef CONFIG_NET_RX_BUSY_POLL diff --git a/net/core/sock.c b/net/core/sock.c index 7dd1263e4c24..1071f9380250 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -988,6 +988,10 @@ set_rcvbuf: sk->sk_max_pacing_rate); break; + case SO_INCOMING_CPU: + sk->sk_incoming_cpu = val; + break; + default: ret = -ENOPROTOOPT; break; @@ -2353,6 +2357,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_max_pacing_rate = ~0U; sk->sk_pacing_rate = ~0U; + sk->sk_incoming_cpu = -1; /* * Before updating sk_refcnt, we must commit prior changes to memory * (Documentation/RCU/rculist_nulls.txt for details) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index bed8886a4b6c..08643a3616af 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -185,6 +185,8 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score += 4; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; } return score; } diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e1fc129099ea..24ec14f9825c 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -375,7 +375,8 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score += 4; } - + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; return score; } @@ -419,6 +420,9 @@ static inline int compute_score2(struct sock *sk, struct net *net, score += 4; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; + return score; } diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 6ac8dad0138a..21ace5a2bf7c 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -114,6 +114,8 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score++; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; } return score; } diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 0aba654f5b91..01bcb49619ee 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -182,10 +182,12 @@ static inline int compute_score(struct sock *sk, struct net *net, score++; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; + return score; } -#define SCORE2_MAX (1 + 1 + 1) static inline int compute_score2(struct sock *sk, struct net *net, const struct in6_addr *saddr, __be16 sport, const struct in6_addr *daddr, @@ -223,6 +225,9 @@ static inline int compute_score2(struct sock *sk, struct net *net, score++; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; + return score; } @@ -251,8 +256,7 @@ begin: hash = udp6_ehashfn(net, daddr, hnum, saddr, sport); matches = 1; - } else if (score == SCORE2_MAX) - goto exact_match; + } } else if (score == badness && reuseport) { matches++; if (reciprocal_scale(hash, matches) == 0) @@ -269,7 +273,6 @@ begin: goto begin; if (result) { -exact_match: if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2))) result = NULL; else if (unlikely(compute_score2(result, net, saddr, sport,
SO_INCOMING_CPU as added in commit 2c8c56e15df3 was a getsockopt() command to fetch incoming cpu handling a particular TCP flow after accept() This commits adds setsockopt() support and extends SO_REUSEPORT selection logic : If a TCP listener or UDP socket has this option set, a packet is delivered to this socket only if CPU handling the packet matches the specified one. This allows to build very efficient TCP servers, using one listener per RX queue, as the associated TCP listener should only accept flows handled in softirq by the same cpu. This provides optimal NUMA behavior and keep cpu caches hot. Note that __inet_lookup_listener() still has to iterate over the list of all listeners. Following patch puts sk_refcnt in a different cache line to let this iteration hit only shared and read mostly cache lines. Signed-off-by: Eric Dumazet <edumazet@google.com> --- include/net/sock.h | 10 ++++------ net/core/sock.c | 5 +++++ net/ipv4/inet_hashtables.c | 2 ++ net/ipv4/udp.c | 6 +++++- net/ipv6/inet6_hashtables.c | 2 ++ net/ipv6/udp.c | 11 +++++++---- 6 files changed, 25 insertions(+), 11 deletions(-)