loratune(1M)															      loratune(1M)

NAME

       loratune - initiate LORA tuneup to improve alignment of processing resources

SYNOPSIS

DESCRIPTION

       The command improves the performance of an HP-UX system in LORA (Locality-Optimizated Resource Alignment) mode, by triggering the kernel to
       do optimization tuning of the system and application memory.

       The command may return before the tuning is complete.  This tuning can continue in the background for several  minutes  after  the  command
       returns.  If the command is interrupted, or the command process is otherwise terminated, no subsequent tuning operations will be initiated,
       but those in progress will continue until completion.

       When no options are specified, all locality domains are tuned.

   Options
       This option limits the tuning to the locality domain specified by
	       lid.

   Application Usage
       In Locality-Optimized Resource Alignment (LORA) mode, performance of applications may improve when their processors  and  the  memory  that
       they  use are aligned in the same locality.  The HP-UX kernel attempts to maintain such alignment at all times, but it is possible for mis-
       alignment to occur when the system workload transitions significantly.  If that happens, the command can be used to  reestablish  alignment
       and improve application performance.

       Here are some examples of workload transition events that may cause misalignment of processing resources:

       o  Starting or terminating an application that consumes a large amount of processor or memory resources.

       o  The workload demand surges far above the normal level and then recedes.

       o  Dynamic platform operations that add or subtract processor or memory resources from the operating system's control.

       If one of those events has occurred, and application performance is not as high as it can be, then it is appropriate to invoke the command.

RETURN VALUES

       The command returns a 0 when successful, and a non-zero value when unsuccessful.

ERRORS

       The command will not initiate any tuning and will return a non-zero value if the user does not have appropriate privilege.

WARNINGS

       The  command  can consume a significant amount of system processing resources to restore optimal alignment.  Ideally, the command should be
       invoked prior to the time when performance is critical, not during the time when performance is critical.  The command  should  be  invoked
       after the workload transition is complete, not during workload transition.  Although tuning can continue in the background for several min-
       utes, it is not necessary to wait any more than five minutes between invoking the command and launching new applications.

EXAMPLES

       If eight instances of SAP were running in localities with locality domain identifiers 4 and 5, and four of those instances were shut  down,
       then it would be appropriate to tuneup the remaining four instances.  An example command would be:

       If  an  HP-UX  system  in LORA mode had one of its cells deactivated, then it would be appropriate to tuneup the entire system.	An example
       command would be:

AUTHOR

       was developed by HP.

SEE ALSO

       mpsched(1), numa_policy(5), lora(7).

							   Itanium(R)-based Systems Only					      loratune(1M)