1. 06 Nov, 2014 33 commits
  2. 05 Nov, 2014 7 commits
    • WANG Cong's avatar
      ipv6: move INET6_MATCH() to include/net/inet6_hashtables.h · 25de4668
      WANG Cong authored
      It is only used in net/ipv6/inet6_hashtables.c.
      
      Cc: David S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      25de4668
    • David S. Miller's avatar
      net: Add and use skb_copy_datagram_msg() helper. · 51f3d02b
      David S. Miller authored
      This encapsulates all of the skb_copy_datagram_iovec() callers
      with call argument signature "skb, offset, msghdr->msg_iov, length".
      
      When we move to iov_iters in the networking, the iov_iter object will
      sit in the msghdr.
      
      Having a helper like this means there will be less places to touch
      during that transformation.
      
      Based upon descriptions and patch from Al Viro.
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      51f3d02b
    • David S. Miller's avatar
      Merge branch 'gue-next' · 1d76c1d0
      David S. Miller authored
      Tom Herbert says:
      
      ====================
      gue: Remote checksum offload
      
      This patch set implements remote checksum offload for
      GUE, which is a mechanism that provides checksum offload of
      encapsulated packets using rudimentary offload capabilities found in
      most Network Interface Card (NIC) devices. The outer header checksum
      for UDP is enabled in packets and, with some additional meta
      information in the GUE header, a receiver is able to deduce the
      checksum to be set for an inner encapsulated packet. Effectively this
      offloads the computation of the inner checksum. Enabling the outer
      checksum in encapsulation has the additional advantage that it covers
      more of the packet than the inner checksum including the encapsulation
      headers.
      
      Remote checksum offload is described in:
      http://tools.ietf.org/html/draft-herbert-remotecsumoffload-01
      
      The GUE transmit and receive paths are modified to support the
      remote checksum offload option. The option contains a checksum
      offset and checksum start which are directly derived from values
      set in stack when doing CHECKSUM_PARTIAL. On receipt of the option, the
      operation is to calculate the packet checksum from "start" to end of
      the packet (normally derived for checksum complete), and then set
      the resultant value at checksum "offset" (the checksum field has
      already been primed with the pseudo header). This emulates a NIC
      that implements NETIF_F_HW_CSUM.
      
      The primary purpose of this feature is to eliminate cost of performing
      checksum calculation over a packet when encpasulating.
      
      In this patch set:
        - Move fou_build_header into fou.c and split it into a couple of
          functions
        - Enable offloading of outer UDP checksum in encapsulation
        - Change udp_offload to support remote checksum offload, includes
          new GSO type and ensuring encapsulated layers (TCP) doesn't try to
          set a checksum covered by RCO
        - TX support for RCO with GUE. This is configured through ip_tunnel
          and set the option on transmit when packet being encapsulated is
          CHECKSUM_PARTIAL
        - RX support for RCO with GUE for normal and GRO paths. Includes
          resolving the offloaded checksum
      
      v2:
        Address comments from davem: Move accounting for private option
        field in gue_encap_hlen to patch in which we add the remote checksum
        offload option.
      
      Testing:
      
      I ran performance numbers using netperf TCP_STREAM and TCP_RR with 200
      streams, comparing GUE with and without remote checksum offload (doing
      checksum-unnecessary to complete conversion in both cases). These
      were run on mlnx4 and bnx2x. Some mlnx4 results are below.
      
      GRE/GUE
          TCP_STREAM
            IPv4, with remote checksum offload
              9.71% TX CPU utilization
              7.42% RX CPU utilization
              36380 Mbps
            IPv4, without remote checksum offload
              12.40% TX CPU utilization
              7.36% RX CPU utilization
              36591 Mbps
          TCP_RR
            IPv4, with remote checksum offload
              77.79% CPU utilization
      	91/144/216 90/95/99% latencies
              1.95127e+06 tps
            IPv4, without remote checksum offload
              78.70% CPU utilization
              89/152/297 90/95/99% latencies
              1.95458e+06 tps
      
      IPIP/GUE
          TCP_STREAM
            With remote checksum offload
              10.30% TX CPU utilization
              7.43% RX CPU utilization
              36486 Mbps
            Without remote checksum offload
              12.47% TX CPU utilization
              7.49% RX CPU utilization
              36694 Mbps
          TCP_RR
            With remote checksum offload
              77.80% CPU utilization
              87/153/270 90/95/99% latencies
              1.98735e+06 tps
            Without remote checksum offload
              77.98% CPU utilization
              87/150/287 90/95/99% latencies
              1.98737e+06 tps
      
      SIT/GUE
          TCP_STREAM
            With remote checksum offload
              9.68% TX CPU utilization
              7.36% RX CPU utilization
              35971 Mbps
            Without remote checksum offload
              12.95% TX CPU utilization
              8.04% RX CPU utilization
              36177 Mbps
          TCP_RR
            With remote checksum offload
              79.32% CPU utilization
              94/158/295 90/95/99% latencies
              1.88842e+06 tps
            Without remote checksum offload
              80.23% CPU utilization
              94/149/226 90/95/99% latencies
              1.90338e+06 tps
      
      VXLAN
          TCP_STREAM
              35.03% TX CPU utilization
              20.85% RX CPU utilization
              36230 Mbps
          TCP_RR
              77.36% CPU utilization
              84/146/270 90/95/99% latencies
              2.08063e+06 tps
      
      We can also look at CPU time in csum_partial using perf (with bnx2x
      setup). For GRE with TCP_STREAM I see:
      
          With remote checksum offload
              0.33% TX
              1.81% RX
          Without remote checksum offload
              6.00% TX
              0.51% RX
      
      I suspect the fact that time in csum_partial noticably increases
      with remote checksum offload for RX is due to taking the cache miss on
      the encapsulated header in that function. By similar reasoning, if on
      the TX side the packet were not in cache (say we did a splice from a
      file whose data was never touched by the CPU) the CPU savings for TX
      would probably be more pronounced.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1d76c1d0
    • Tom Herbert's avatar
      gue: Receive side of remote checksum offload · a8d31c12
      Tom Herbert authored
      Add processing of the remote checksum offload option in both the normal
      path as well as the GRO path. The implements patching the affected
      checksum to derive the offloaded checksum.
      Signed-off-by: default avatarTom Herbert <therbert@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a8d31c12
    • Tom Herbert's avatar
      gue: TX support for using remote checksum offload option · b17f709a
      Tom Herbert authored
      Add if_tunnel flag TUNNEL_ENCAP_FLAG_REMCSUM to configure
      remote checksum offload on an IP tunnel. Add logic in gue_build_header
      to insert remote checksum offload option.
      Signed-off-by: default avatarTom Herbert <therbert@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b17f709a
    • Tom Herbert's avatar
      gue: Protocol constants for remote checksum offload · c1aa8347
      Tom Herbert authored
      Define a private flag for remote checksun offload as well as a length
      for the option.
      Signed-off-by: default avatarTom Herbert <therbert@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c1aa8347
    • Tom Herbert's avatar
      udp: Changes to udp_offload to support remote checksum offload · e585f236
      Tom Herbert authored
      Add a new GSO type, SKB_GSO_TUNNEL_REMCSUM, which indicates remote
      checksum offload being done (in this case inner checksum must not
      be offloaded to the NIC).
      
      Added logic in __skb_udp_tunnel_segment to handle remote checksum
      offload case.
      Signed-off-by: default avatarTom Herbert <therbert@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e585f236