numa_sched_launch(5)						File Formats Manual					      numa_sched_launch(5)

NAME

       numa_sched_launch - change process default launch policy

VALUES

   Failsafe
   Default
   Allowed values
   Recommended values
       unless the application requires explicit different behavior.

DESCRIPTION

       The  dynamic tunable controls the default launch policy for newly created processes.  The process launch policy controls the initial place-
       ment of the child process at creation time.  The scheduler can migrate threads from one locality domain (LDOM)  to  another  to	distribute
       workload  for better throughput and responsiveness.  The default launch policy is applicable only to processes that have no explicit launch
       policy, processor binding, or LDOM binding applied to them (see mpctl(2) for details).

       There are three possible values of this tunable:

	      This value explicitly disables any change in the default launch policy for
		   processes irrespective of the system configuration.	A newly created process will be placed using  the  legacy  default  launch
		   policy.

	      This is the default and recommended value.
		   HP-UX  will autosense the right policy setting based on system configuration.  This policy directs HP-UX to optimize the launch
		   policy for multi-process applications that share data.  Such applications can get better performance when the applications  are
		   packed together in the same LDOM.  The policy will cause child processes created using to be placed in the same locality domain
		   as the parent process.  Note that a different default launch policy may be used in the future with  new  system  configurations
		   for improved application performance when this tunable is enabled.

		   Processes  created  using  will  be	treated as if they are a new application and will continue to be launched using the legacy
		   default launch policy.

	      This value explicitly enables the new default launch policy for processes.
		   A process created using is placed in the same locality domain as its parent process irrespective of the system configuration.

   Who Is Expected to Change This Tunable?
       System administrators who prefer to explicitly control the default launch policy  for  applications  even  when	LORA  (Locality  Optimized
       Resource Alignment) mode is enabled (see numa_policy(5) for details).

   Restrictions on Changing
       The  tunable  changes  take effect immediately.	However, changes to this tunable will not affect processes that are already created.  Such
       processes will need to be stopped and restarted to be launched with a modified tunable setting.

   When Should the Value of This Tunable Be Changed to 0?
       The value of should be set to to preserve the legacy process default launch policy even when the system is configured in LORA mode.

   When Should the Value of This Tunable Be Changed to 1?
       The value of should be set to to improve the performance of multi-process applications.

   When Should the Value of This Tunable Be Changed to 2?
       The value of should be set to when a multi-process application is likely to see improved performance even if the system is  not	configured
       for LORA mode.

   What Are the Side Effects of Changing the Value?
       The  distribution  of  CPU utilization across the system will change.  This situation can result in a change in performance.  The change in
       performance is highly dependent on the workload and the partition configuration.

   What Other Tunable Values Should Be Changed at the Same Time?
       None.

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.

       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  tun-
       able  values,  consult  the documentation for the kernel software being installed.  For information about optional kernel software that was
       factory installed on your system, see at

AUTHOR

       was developed by HP.

SEE ALSO

       fork(2), mpctl(2), vfork(2), numa_policy(5).

							     Tunable Kernel Parameters					      numa_sched_launch(5)