kmem_va_cache_enable(5)Itanium(R)-based Systems Only kmem_va_cache_enable(5)NAMEkmem_va_cache_enable - Tunable to enable or disable improved kernel
virtual address caching.
VALUES
Failsafe
Default
Allowed values
DESCRIPTION
The tunable enables (1) or disables (0) the new infrastructure for man‐
aging the kernel virtual address space to improve the performance of
HP-UX on high end Integrity servers.
This infrastructure provides a new mechanism to cache the kernel vir‐
tual addresses on top of conventional virtual address resource maps,
which improves the performance of kernel virtual address allocation and
free paths.
Disabling this new infrastructure will use existing resource map infra‐
structure, which may cause certain lock contention on high end
integrity servers on certain kernel intensive work loads.
must be a positive integer, either 0 (off) or 1 (on). System may
decides to turn off this tunable depending on the patch level, the sys‐
tem is patched with.
Who Is Expected to Change This Tunable?
Administrators investigating the performance characteristics of kernel
intensive workloads.
Restrictions on Changing
This tunable is present only on Itanium-based platforms. It is not
available on PA-RISC platforms.
What are the Side Effects of enabling the tunable?
New infrastructure may consume slightly more kernel dynamic memory on
certain kind of workloads. The actual performance impact will depend on
the data access pattern and the workload.
When does this tunable change take effect?
Changes to this tunable require a system reboot to take effect.
What Other Tunables should be changed at the same time?
None.
ERRORS
An invalid value is entered that is neither 0 nor 1.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parame‐
ter 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 val‐
ues. For information about the effects of installation on tunable val‐
ues, see 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
was developed by HP.
SEE ALSOkctune(1),
Tunable Kernel Parameters kmem_va_cache_enable(5)