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The Most Incomplete Guide to Performance Tuning
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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)
