loratune(1M)loratune(1M)NAMEloratune - initiate LORA tuneup to improve alignment of processing
resources
SYNOPSISDESCRIPTION
The command improves the performance of an HP-UX system in LORA (Local‐
ity-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 oth‐
erwise 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 misalign‐
ment 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:
· 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 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 minutes, 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 com‐
mand would be:
AUTHOR
was developed by HP.
SEE ALSOmpsched(1), numa_policy(5), lora(7).
Itanium(R)-based Systems Only loratune(1M)
