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kmem_va_cache_enable(5)	 Itanium(R)-based Systems Only kmem_va_cache_enable(5)

NAME
       kmem_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 ALSO
       kctune(1),

			   Tunable Kernel Parameters   kmem_va_cache_enable(5)

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