Index for Section 5

Alphabetical listing for S

Bottom of page

sys_attrs_socket(5)
NAME
  sys_attrs_socket - socket subsystem attributes

DESCRIPTION
  This reference page lists and describes attributes for the Socket (socket)
  kernel subsystem. Refer to the sys_attrs(5) reference page for an
  introduction to the topic of kernel subsystem attributes.

  mbuf_ext_lock_count
      The number of lock entries to use when taking a lock reference on an
      external cluster mbuf (more is better).

      Default value: 64 (entries)

      Minimum value: 0

      Maximum value: 8192

      The mbuf_ext_lock_count attribute is useful only on SMP machines where
      locks are used.

  pftimerbindcpu
      The CPU number to which to bind the protocol timer thread.

      Default value: 0

      Minimum value: 0

      Maximum value: UINT_MAX, or 4 billion

  sb_max
      Maximum size of the socket buffer.

      Default value: SB_MAX, or 1048576 (bytes)

      Minimum value: 1

      Maximum value: 4 billion

  sbcompress_threshold
      The maximum size of packets to be copied into existing mbuf clusters,
      or compressed. Only packets of size less than sbcompress_threshold
      minus 1 are copied into existing mbuf clusters.

      Default value: 0 (bytes)

      Minimum value: 0

      Maximum value: UINT_MAX, or 4 billion

      If the sbcompress_threshold attribute value is 0, mbuf cluster
      compression is disabled.

  sobacklog_drops
      A read-only attribute that is incremented when a received SYN packet is
      dropped because the number of queued SYN_RCVD connections for a socket
      is equal to that socket's backlog limit. The initial value is 0.

  sobacklog_hiwat
      A read-only attribute that shows the maximum number of pending requests
      to any of the server sockets in the system. The initial value is 0.

  somaxconn
      Maximum number of pending TCP connections (the socket listen queue
      limit).

      Default value: 1024 (connections)

      Minimum value: 0

      Maximum value: 65535

      If the listen queue connection limit is too small, incoming connect
      requests may be dropped. Pending TCP connections can be caused by lost
      packets in the Internet or denial of service attacks.

  somaxconn_drops
      A read-only attribute that is  incremented when a received SYN packet
      is dropped because the number of queued SYN_RCVD connections for a
      socket is equal to the value of the somaxconn attribute. The initial
      value is 0.

  sominconn
      Minimum number of pending TCP connections (the socket listen queue
      backlog). The attribute controls how many SYN packets can be handled
      simultaneously before additional requests are discarded.

      Default value: 0 (connections)

      Minimum value: 0

      Maximum value: 65535

      The value of the sominconn attribute overrides the application-specific
      backlog if the sominconn value is greater than the backlog requested by
      the application.

  umc A value that enables (1) or disables (0)	socket writes without the
      need for a user space to kernel space copy operation. The umc (unified
      mbuf cache) attribute is used in conjunction with the mmap(2) system
      call.

      Default value: 0 (disabled)

  umc_min_len
      The size of the umc (unified mbuf cache) buffer.

      Default value: 1024 (bytes)

      Minimum value: 0

      Maximum value: INT_MAX, or 2 billion

SEE ALSO
  sys_attrs(5)

  Tuning Tru64 UNIX for Internet Servers at the following location:
  http://www.tru64unix.compaq.com/faqs/publications/internet/TITLE.HTM.

  System Configuration and Tuning

Index for Section 5

Alphabetical listing for S

Top of page