src/modprobe.d/no-copybreak.conf

   1 #
   2 # Some network interface drivers employ a scheme known as "copybreak"
   3 # in which they make a copy of a received skb if the size of the
   4 # buffer is below a particular threshold, then return the original
   5 # receive skb back to the pool.  Since these drivers initially
   6 # allocate a buffer size that is larger than the largest possible
   7 # packet, this scheme returns that large buffer to the pool quickly,
   8 # and uses a smaller one.
   9 #
  10 # The primary benefit of copybreak is better memory utilization.  On
  11 # systems where the data is ultimately going to be copied out to user
  12 # space, the copybreak scheme is "low cost" because it has the side
  13 # benefit of priming the cache for that later copy.  But on a router
  14 # that only touches the header fields of a received packet, the cost
  15 # can be relatively higher.  And on modern systems the memory savings
  16 # is rarely an important consideration.
  17 #
  18 # Some of the drivers that employ copybreak make the feature
  19 # configurable via a module parameter.  This file disables copybreak
  20 # in some of those drivers.  Generally this results in an improvement
  21 # in forwarding performance for traffic using these drivers.
  22 #
  23
  24 options 3c515 rx_copybreak=0
  25 options 3c59x rx_copybreak=0
  26 options bcm63xx copybreak=0
  27 options cxgb copybreak=0
  28 options e1000 copybreak=0
  29 options e1000e copybreak=0
  30 options epic100 rx_copybreak=0
  31 options fealnx rx_copybreak=0
  32 options hamachi rx_copybreak=0
  33 options ixgb copybreak=0
  34 options natsemi rx_copybreak=0
  35 options pch_gbe copybreak=0
  36 options pcnet32 rx_copybreak=0
  37 options sis190 rx_copybreak=0
  38 options sky2 copybreak=0
  39 options starfire rx_copybreak=0
  40 options sundance rx_copybreak=0
  41 options typhoon rx_copybreak=0
  42 options via-rhine rx_copybreak=0
  43 options via-velocity rx_copybreak=0
  44 options yellowfin rx_copybreak=0