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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-10-06 17:28:29 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-10-06 17:28:29 -0700 |
| commit | bcdce7195e0eab55b37dbd53be53057f38006380 (patch) | |
| tree | b4480a2e43561adf2060d1b8da818535cc91dc04 | |
| parent | bd32cafc4707ccc1e66fafdb47fac42217569070 (diff) | |
| download | linux-stable-bcdce7195e0eab55b37dbd53be53057f38006380.tar.gz linux-stable-bcdce7195e0eab55b37dbd53be53057f38006380.tar.bz2 linux-stable-bcdce7195e0eab55b37dbd53be53057f38006380.zip | |
net: speedup sk_wake_async()
An incoming datagram must bring into cpu cache *lot* of cache lines,
in particular : (other parts omitted (hash chains, ip route cache...))
On 32bit arches :
offsetof(struct sock, sk_rcvbuf) =0x30 (read)
offsetof(struct sock, sk_lock) =0x34 (rw)
offsetof(struct sock, sk_sleep) =0x50 (read)
offsetof(struct sock, sk_rmem_alloc) =0x64 (rw)
offsetof(struct sock, sk_receive_queue)=0x74 (rw)
offsetof(struct sock, sk_forward_alloc)=0x98 (rw)
offsetof(struct sock, sk_callback_lock)=0xcc (rw)
offsetof(struct sock, sk_drops) =0xd8 (read if we add dropcount support, rw if frame dropped)
offsetof(struct sock, sk_filter) =0xf8 (read)
offsetof(struct sock, sk_socket) =0x138 (read)
offsetof(struct sock, sk_data_ready) =0x15c (read)
We can avoid sk->sk_socket and socket->fasync_list referencing on sockets
with no fasync() structures. (socket->fasync_list ptr is probably already in cache
because it shares a cache line with socket->wait, ie location pointed by sk->sk_sleep)
This avoids one cache line load per incoming packet for common cases (no fasync())
We can leave (or even move in a future patch) sk->sk_socket in a cold location
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/sock.h | 3 | ||||
| -rw-r--r-- | net/socket.c | 3 |
2 files changed, 5 insertions, 1 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 1621935aad5b..98398bdec57d 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -504,6 +504,7 @@ enum sock_flags { SOCK_TIMESTAMPING_SOFTWARE, /* %SOF_TIMESTAMPING_SOFTWARE */ SOCK_TIMESTAMPING_RAW_HARDWARE, /* %SOF_TIMESTAMPING_RAW_HARDWARE */ SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */ + SOCK_FASYNC, /* fasync() active */ }; static inline void sock_copy_flags(struct sock *nsk, struct sock *osk) @@ -1396,7 +1397,7 @@ static inline unsigned long sock_wspace(struct sock *sk) static inline void sk_wake_async(struct sock *sk, int how, int band) { - if (sk->sk_socket && sk->sk_socket->fasync_list) + if (sock_flag(sk, SOCK_FASYNC)) sock_wake_async(sk->sk_socket, how, band); } diff --git a/net/socket.c b/net/socket.c index 75655365b5fd..d53ad11558c3 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1100,11 +1100,14 @@ static int sock_fasync(int fd, struct file *filp, int on) fna->fa_next = sock->fasync_list; write_lock_bh(&sk->sk_callback_lock); sock->fasync_list = fna; + sock_set_flag(sk, SOCK_FASYNC); write_unlock_bh(&sk->sk_callback_lock); } else { if (fa != NULL) { write_lock_bh(&sk->sk_callback_lock); *prev = fa->fa_next; + if (!sock->fasync_list) + sock_reset_flag(sk, SOCK_FASYNC); write_unlock_bh(&sk->sk_callback_lock); kfree(fa); } |