pstatectl(1M)pstatectl(1M)NAMEpstatectl - control processor performance states
SYNOPSIS
cpu] pstate| interval]
DESCRIPTION
The command is used to control processor performance states (P-states).
On systems with supported processors and firmware, processor perfor‐
mance states can reduce power consumption.
A supported processor implements a series of performance states, num‐
bered from P0 to Pn, where n is implementation dependent. Each subse‐
quent P-state consumes less power but offers less performance than the
previous state.
provides access to both static and dynamic performance state usage
modes. In static mode, the system remains in a specified P-state,
where power consumption and performance are reduced by a fixed amount.
In dynamic mode, HP-UX will adjust the processors' P-states individu‐
ally, in response to the workload running on the system.
Enabling dynamic processor performance states will generally have a
negligible effect on system performance, while at the same time reduc‐
ing power consumption when the system is not fully loaded.
Options
recognizes the following options:
The operation will apply to the specified
processor only. If is not specified, the opera‐
tion applies to the whole system.
The "status" operation will report detailed status for each pro‐
cessor.
Otherwise, a summary of the system state is
reported.
Operands
recognizes the following operands; only one operand at a time can be
specified on the command line:
Enable the dynamic P-states mode (processors will adjust perfor‐
mance to match the workload).
Disable the P-states (processors will always be at maximum per‐
formance).
Enable static mode (processors will always be in the specified
P-state).
If the specified state is higher than is sup‐
ported, the highest supported state is used
instead. The state may be specified as a number,
or in P-state notation (for example, P0).
Enable dynamic P-states mode within the range of states speci‐
fied.
and should be supplied as specified under the
option.
Report information about the system's P-state capabilities,
the current P-state mode (static or dynamic), and
whether HP-UX has control over processor
P-states. If was specified, each processor's
current P-state and operating mode are displayed.
Display a table listing the power consumption and relative per‐
formance of each P-state.
Print the number of the highest implemented P-state on the sys‐
tem.
If the system does not support P-states, the num‐
ber is 0.
Change the time interval between dynamic mode state changes to
the
specified duration. The minimum is 0.01 seconds,
and the maximum is 600 seconds.
EXTERNAL INFLUENCES
On some systems, the Onboard Administrator may take control of P-states
away from the operating system (for instance, when iLO is used to place
the system in Static High Performance or Static Low Power mode).
If HP-UX does not have control over processor performance states, the
command will still work normally. However, any changes made to P-state
modes will have no effect until HP-UX regains control. The command
will report whether HP-UX currently has control over P-states.
RETURN VALUE
returns the following values:
Successful completion.
Command failed.
DIAGNOSTICS
Make sure that the system has Itanium(R) 2 9100 series or later
processors, and that the installed system firmware supports P-
states.
EXAMPLES
To enable dynamic P-states on the system:
To disable dynamic P-states on the system (all processors will be in
maximum performance mode):
or
To restrict the system to P0 and P1 only:
DEPENDENCIES
Processor performance states require Itanium(R) 2 9100 series proces‐
sors or later models. Some systems require a firmware update to use
processor performance states.
AUTHOR
was developed by HP.
SEE ALSO
(Itanium(R)-based Systems Only) pstatectl(1M)
