Tunable Kernel Parameters
NAME [Toc] [Back]
ksi_send_max - limit on number of queued signals per process
VALUES [Toc] [Back]
Allowed Values [Toc] [Back]
32 through maxint (0x7fffffff)
DESCRIPTION [Toc] [Back]
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?
Restrictions on Changing [Toc] [Back]
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
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 [Toc] [Back]
All HP-UX kernel tunable parameters are release specific. This
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: Sep 2004
Tunable Kernel Parameters
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 parameter 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
AUTHOR [Toc] [Back]
ksi_send_max was developed by HP.
SEE ALSO [Toc] [Back]
kill(2), sigqueue(2), ksi_alloc_max(5).
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: Sep 2004 [ Back ]