Using Power Management

To enable power management (PM), you first need to set the PM policy in the Oracle Integrated Lights Out Manager (ILOM) 3.0 firmware. This section summarizes the information that you need to be able to use PM with the Oracle VM Server for SPARC software.

For more information about ILOM, see the following:

• “Monitoring Power Consumption” in the Oracle Integrated Lights Out Manager (ILOM) 3.0 CLI Procedures Guide

• Oracle Integrated Lights Out Manager (ILOM) 3.0 Feature Updates and Release Notes

The power policy governs system power usage at any point in time. The following power policies are supported, assuming that the underlying platform has implemented PM features:

• Performance. The system is allowed to use all the power that is available.

• Elastic. The system power usage is adapted to the current utilization level. For example, the power state of resources is reduced as utilization decreases.

Following are the PM features:

• CPU core auto-disabling. When the elastic policy is in effect, the Logical Domains Manager automatically disables a CPU core when all the threads (strands) on that core have been disabled. This feature is only available for the UltraSPARC T2, UltraSPARC T2 Plus, SPARC T3, and SPARC T4 platforms.

• CPU clock cycle skip. Starting with the Oracle VM Server for SPARC 2.0 release, Logical Domains Manager can automatically adjust the CPU clock cycle skip. This feature is only available for SPARC T3 and SPARC T4 platforms. The adjustment can increase or decrease the number of clock cycles that are skipped to keep all domains within the power utilization thresholds. PM determines whether to make such adjustments based on CPU utilization. When the system uses the performance policy, the number of clock cycles that are skipped is automatically adjusted to being none.

• Memory operations in deep idle mode. Starting with the Oracle VM Server for SPARC 2.0 release, when SPARC T3 and SPARC T4 platforms have the elastic policy in effect, they automatically configure under-utilized memory to operate in a deeper idle mode to save power.

• Power limit. You can set a power limit on SPARC T3 and SPARC T4 platforms to restrict the power draw of a system. If the power draw is greater than the power limit, PM techniques are used to reduce power. You can use the ILOM service processor (SP) to set the power limit.

  See the following documents:

  • Oracle Integrated Lights Out Manager (ILOM) 3.0 CLI Procedures Guide

  • Oracle Integrated Lights Out Manager (ILOM) 3.0 Feature Updates and Release Notes

  You can use the ILOM interface to set a power limit, grace period, and violation action. If the power limit is exceeded for more than the grace period, the violation action is performed.

  If the current power draw exceeds the power limit, an attempt is made to reduce the power state of resources that can be power-managed. If the power draw drops below the power limit, the power state of those resources is permitted to increase. If the system has the elastic policy in effect, an increase in the power state of resources is driven by the utilization level.

  When a system has the elastic policy in effect, some domain configuration modifications are first validated to confirm that the power limit is not exceeded. If the power limit is exceeded, only some of the resources might be modified or added as requested. If the power limit is later increased, you can then add any resources that were unsuccessfully modified.

  If a domain's load causes resources to consume more power, only the resources that maintain the power draw being under the power limit are successfully powered up.

• Solaris Power Aware Dispatcher (PAD). Starting with the Oracle VM Server for SPARC 3.0 release, a guest domain that runs the Oracle Solaris 11.1 OS uses the power-aware dispatcher (PAD) on SPARC T3 and SPARC T4 systems to minimize power consumption from idle or under-utilized resources. PAD, instead of the Logical Domains Manager, adjusts the CPU clock cycle skip level.

For instructions on configuring the power policy by using the ILOM 3.0 firmware CLI, see “Monitoring Power Consumption” in the Oracle Integrated Lights Out Manager (ILOM) 3.0 CLI Procedures Guide.