Hyper-Threading, available starting with HP-UX 11i v3 (B.11.31),
enables you to use multiple execution threads per core. (Cores were
formerly known as CPUs.) Each execution thread is a logical CPU.
Utilization is based on the usage of a core—not a logical
CPU. For example, assume a four-core system has Hyper-Threading enabled
so that it has eight logical CPUs. If the system has four processes,
each consuming an entire logical CPU, the reported utilization depends
on where those processes are. If the processes are on only two cores,
the utilization is 50% (2/4). With the processes distributed across
all four cores though, each process can consume an entire core, resulting
in a utilization of 100%.
When fss groups are being used, gWLM disables Hyper-Threading
for the default pset, where fss groups are created, to optimize workload
performance.
When an SRD is undeployed, gwlmagent restores
the lcpu_attr tunable to the value it had
when the system booted. This value can be different from the value
in effect before deployment if kctune was used
without a reboot.
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