NAME
ksi_alloc_max — system-wide limit of queued signals that can be allocated
VALUES
Allowed Values
32 through maxint (0x7fffffff)
DESCRIPTION
ksi_alloc_max
is the system-wide limit on the number of queued signals that can be
allocated and in use.
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.
Since the default value is based on the number of processes but the
usage is thread based, a large number of threads per process which
use queued signals would require a raising the tunable value.
When
EAGAIN
is returned by applications using queued signals, this 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?
Excessive memory consumption due to queued signals usage, and
if too low, failure of applications using queued signals.
What Other Tunable Values Should Be Changed at the Same Time?
ksi_send_max
to limit the number of queued signals per process.
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
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.
AUTHOR
ksi_alloc_max
was developed by HP.
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