dnlc_hash_locks(5)dnlc_hash_locks(5)NAMEdnlc_hash_locks - number of locks for the Directory Name Lookup Cache
The minimum value allowed is The maximum value allowed is The value is
further constrained in that it must be be a power of 2, and it must be
equal to or less than one-eighth the number of DNLC entries Specify a
positive integer value.
To speed up the search through directories in the kernel, there is a
memory resident cache of directories called the During a filename
lookup in the kernel, any directories or files encountered are retained
in the DNLC for future reference. The DLNC is managed in a Least
Recently Used fashion. The dictates the number of lock groups that
will be used to manage the directory entries in the DNLC hash chains.
Who Is Expected to Change This Tunable?
HP-UX system administrators.
Restrictions on Changing
This tunable is static. Any changes to the value of this tunable
require a system reboot before taking effect.
When Should the Value of This Tunable Be Raised?
The value may need to be raised to reduce lock contention and improve
filename lookup performance when running applications which require
large numbers of file name accesses.
What are the Side Effects of Raising the Value?
More system memory will be consumed to allocate locks for the DNLC.
When Should the Value of This Tunable Be Lowered?
The value can be lowered to limit the number of locks allocated for the
DNLC and to reduce memory consumption.
What are the Side Effects of Lowering the Value?
Less system memory will be consumed for the DNLC locks upon system
reboot. Operations requiring filename lookup (for example, (see
open(2)) may experience performance degradation.
What Other Tunable Values Should Be Changed at the Same Time?
The value of must be equal to or greater than eight times the value of
All HP-UX kernel tunable parameters are release specific. This parame‐
ter may be removed or have its meaning changed in future releases of
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 val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
was developed by HP.
SEE ALSOkctune(1M), smh(1M), gettune(2), settune(2).
Tunable Kernel Parameters dnlc_hash_locks(5)