loratune.1m (2010 09)

l
loratune(1M) loratune(1M)
(Itanium(R)-based Systems Only)
NAME
loratune - initiate LORA tuneup to improve alignment of processing resources
SYNOPSIS
loratune [-l lid]...
DESCRIPTION
The
loratune 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 applica-
tion memory.
The
loratune 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 com-
mand process is otherwise terminated, no subsequent tuning operations will be initiated, but those in pro-
gress will continue until completion.
When no options are specified, all locality domains are tuned.
Options
-l lid 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 misalignment to occur when the
system workload transitions significantly. If that happens, the
loratune command can be used to rees-
tablish alignment and improve application performance.
Here are some examples of workload transition events that may cause misalignment of processing
resources:
• Starting or terminating an application that consumes a large amount of processor or memory
resources.
• The workload demand surges far above the normal level and then recedes.
• 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
loratune command.
RETURN VALUES
The
loratune command returns a 0 when successful, and a non-zero value when unsuccessful.
ERRORS
The
loratune command will not initiate any tuning and will return a non-zero value if the user does
not have appropriate privilege.
WARNINGS
The
loratune 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 criti-
cal, not during the time when performance is critical. The command should be invoked after the work-
load transition is complete, not during workload transition. Although tuning can continue in the back-
ground for several minutes, it is not necessary to wait any more than five minutes between invoking the
loratune 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:
loratune -l 4 -l 5
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:
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1