sys_attrs_socket(5)sys_attrs_socket(5)NAMEsys_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.
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.
The CPU number to which to bind the protocol timer thread.
Default value: 0
Minimum value: 0
Maximum value: UINT_MAX, or 4 billion
Maximum size of the socket buffer.
Default value: SB_MAX, or 1048576 (bytes)
Minimum value: 1
Maximum value: 4 billion
The maximum size of packets to be copied into existing mbuf
clusters, or compressed. Only packets of size less than sbcom‐
press_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.
A read-only attribute that is incremented when a received SYN
packet is dropped because the number of queued SYN_RCVD connec‐
tions for a socket is equal to that socket's backlog limit. The
initial value is 0.
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.
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 con‐
nect requests may be dropped. Pending TCP connections can be
caused by lost packets in the Internet or denial of service
attacks.
A read-only attribute that is incremented when a received SYN
packet is dropped because the number of queued SYN_RCVD connec‐
tions for a socket is equal to the value of the somaxconn
attribute. The initial value is 0.
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 dis‐
carded.
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.
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)
The size of the umc (unified mbuf cache) buffer.
Default value: 1024 (bytes)
Minimum value: 0
Maximum value: INT_MAX, or 2 billion
SEE ALSOsys_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
sys_attrs_socket(5)
