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authorEric Dumazet <eric.dumazet@gmail.com>2009-10-06 17:28:29 -0700
committerDavid S. Miller <davem@davemloft.net>2009-10-06 17:28:29 -0700
commitbcdce7195e0eab55b37dbd53be53057f38006380 (patch)
treeb4480a2e43561adf2060d1b8da818535cc91dc04 /include
parentbd32cafc4707ccc1e66fafdb47fac42217569070 (diff)
downloadop-kernel-dev-bcdce7195e0eab55b37dbd53be53057f38006380.zip
op-kernel-dev-bcdce7195e0eab55b37dbd53be53057f38006380.tar.gz
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>
Diffstat (limited to 'include')
-rw-r--r--include/net/sock.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 1621935..98398bd 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);
}
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