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ksi_send_max.5 (2010 09)

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ksi_send_max(5) ksi_send_max(5)
(Tunable Kernel Parameters)
NAME
ksi_send_max - limit on number of queued signals per process
VALUES
Default
32
Allowed Values
32 through maxint (0x7fffffff)
DESCRIPTION
ksi_send_max is the per process limit on the number of queued signals that can be posted by a sender
and currently pending at receivers. The enforced limit is per process sender based. ksi stands for "kernel
signal information" and identifies entries with information about queued signals. There is one per
queued signal. Queued signals are used by the
sigqueue system call, timer expiration, POSIX real time
message queues, and asynchronous I/O. User generated signals (via
kill and raise) are not queued.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
Frequent or heavy use of facilities which use queued signals, may require raising this value. When
[EAGAIN] is returned by the
sigqueue system call, the tunable should be raised.
What Are the Side Effects of Raising the Value?
Increased memory usage, but only if used. Every allocated entry is 96 bytes.
When Should the Value of This Tunable Be Lowered?
Only to control the applications’ usage of queued signals.
What Are the Side Effects of Lowering the Value?
If too low, failure of applications using queued signals may fail.
What Other Tunable Values Should Be Changed at the Same Time?
ksi_alloc_max to limit the number of queued signals system-wide. Since
ksi_alloc_max is per
system based and
ksi_send_max is per process based, the ksi_alloc_max
tunable should always be
greater.
Note that the default value for
ksi_send_max is 32, and for ksi_alloc_max
is ’nproc * 8’.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-
ter values. After installation, some tunable parameters may no longer be at the default or recommended
values. For information about the effects of installation on tunable values, consult the documentation for
the kernel software being installed. For information about optional kernel software that was factory
installed on your system, see HP-UX Release Notes at
http://www.hp.com/go/hpux-core-docs
.
AUTHOR
ksi_send_max was developed by HP.
SEE ALSO
kctune(1M), kill(2), sigqueue(2), ksi_alloc_max(5).
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

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