1. 16 Nov, 2008 8 commits
  2. 14 Nov, 2008 1 commit
    • Eric Dumazet's avatar
      net: speedup dst_release() · ef711cf1
      Eric Dumazet authored
      
      
      During tbench/oprofile sessions, I found that dst_release() was in third position.
      
      CPU: Core 2, speed 2999.68 MHz (estimated)
      Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000
      samples  %        symbol name
      483726    9.0185  __copy_user_zeroing_intel
      191466    3.5697  __copy_user_intel
      185475    3.4580  dst_release
      175114    3.2648  ip_queue_xmit
      153447    2.8608  tcp_sendmsg
      108775    2.0280  tcp_recvmsg
      102659    1.9140  sysenter_past_esp
      101450    1.8914  tcp_current_mss
      95067     1.7724  __copy_from_user_ll
      86531     1.6133  tcp_transmit_skb
      
      Of course, all CPUS fight on the dst_entry associated with 127.0.0.1 
      
      Instead of first checking the refcount value, then decrement it,
      we use atomic_dec_return() to help CPU to make the right memory transaction
      (ie getting the cache line in exclusive mode)
      
      dst_release() is now at the fifth position, and tbench a litle bit faster ;)
      
      CPU: Core 2, speed 3000.1 MHz (estimated)
      Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000
      samples  %        symbol name
      647107    8.8072  __copy_user_zeroing_intel
      258840    3.5229  ip_queue_xmit
      258302    3.5155  __copy_user_intel
      209629    2.8531  tcp_sendmsg
      165632    2.2543  dst_release
      149232    2.0311  tcp_current_mss
      147821    2.0119  tcp_recvmsg
      137893    1.8767  sysenter_past_esp
      127473    1.7349  __copy_from_user_ll
      121308    1.6510  ip_finish_output
      118510    1.6129  tcp_transmit_skb
      109295    1.4875  tcp_v4_rcv
      Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ef711cf1
  3. 13 Nov, 2008 9 commits
  4. 12 Nov, 2008 12 commits
  5. 11 Nov, 2008 10 commits