pwr_idle_ctl.5 (2010 09)

p
pwr_idle_ctl(5)
Integrity Systems Only
pwr_idle_ctl(5)
(Tunable Kernel Parameters)
NAME
pwr_idle_ctl - control power consumption in idle processors on Integrity platforms
VALUES
Fail Safe
0 (power control feature off)
Default
0 (power control feature off)
Allowed values
0 (power control feature off)
1 through 5 (power control feature dial)
DESCRIPTION
The
pwr_idle_ctl tunable can be used to dynamically control the power consumption of idle proces-
sors on Integrity systems. The tunable can be changed from
1 through 5, where 1 represents the least
power saving and
5 represents the maximum power saving in idle processors. Equal or greater idle pro-
cessor power saving is guaranteed by increasing the value of this tunable.
When the tunable is set to
0, the power saving feature is turned off.
This tunable is supported only on Integrity platforms with Intel(R) Itanium(R) Processors 9000 Series and
later. It is not supported on PA-RISC platforms.
This tunable is not supported while running in a Integrity Virtual Machine guest environment.
Who Is Expected to Change This Tunable?
System administrators who want to control power utilization on idle processors.
Restrictions on Changing
The tunable will not take effect on processors belonging to processor sets whose lcpu attribute is turned
ON.
This tunable is dynamic.
When Should the Tunable Be Turned On?
The tunable should be turned on to save power on idle systems.
What Are the Side Effects of Turning the Tunable On?
Some workloads may experience performance degradation when the tunable is enabled.
What Are the Side Effects of Turning the Tunable Off?
With the tunable turned off, the system administrator may not take advantage of possible power saving
on idle systems.
What Other Tunables Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
Increase in power savings is not guaranteed with an increase in tunable values in certain environments.
Enabling this tunable may impact the performance of certain types of workloads.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-
ter values. After installation, some tunable parameters may no longer be at the default or recommended
values. For information about the effects of installation on tunable values, consult the documentation for
the kernel software being installed. For information about optional kernel software that was factory
installed on your system, see HP-UX Release Notes at
http://www.hp.com/go/hpux-core-docs.
AUTHOR
pwr_idle_ctl was developed by HP.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1