1. 07 Oct, 2009 1 commit
    • Eric Dumazet's avatar
      net: speedup sk_wake_async() · bcdce719
      Eric Dumazet authored
      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: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bcdce719
  2. 06 Oct, 2009 23 commits
  3. 05 Oct, 2009 16 commits