Post by cjcain on Jan 19, 2021 13:56:11 GMT
1. We are looking to add a writable power mode parameter.
The power mode would define, at a high level, the algorithm in which the processor frequency is adjusted to control how much power is being consumed. This allows a system to be configured based on the power or performance needs of its users. The mode should be able to be written prior to powering on as well as being changed while the system is running.
Example power modes:
Maximum Performance - processor will always be running at highest speeds possible (power usage not considered)
This mode would be used for workloads where performance is the top priority.
Dynamic Performance / On Demand - processor will run at the highest speeds until the utilization drops (power saved when system not busy)
This mode is a compromise giving maximum performance when busy, while still saving power when the system is not under heavy load.
Power Save - processor will run at a reduced speed to save power
This could be used for systems running batch jobs or off-shit applications not requiring high performance
Linux systems refer to the power mode as a "governor"
Documents discussing implementation / usage of power modes / governors
Arch Linux: CPU Frequency Scaling
Intel White Paper: Power Management in Intel Architecture Servers
IBM White Paper: IBM EnergyScale for POWER9 Processor-Based Systems (see PowerVM Specific Features)
2. We would like to add additional parameters related to support Idle Power Save. This allows the system owner to define when a system should be considered idle vs active. When a system is idle, the processor frequency can be automatically reduced to lower power consumption and then restore performance when the system becomes active again. This can be used to ensure systems can meet EnergyStar compliance.
The following parameters would be desired:
- Idle Power Saver Enabled / Disabled
Defines if this feature is enabled or not
- Enter Power Save Utilization threshold (percentage)
Defines the lower threshold of utilization. When the system drops down to or below this threshold, it will be ready to go to Idle Power Save state.
- Enter Power Save Delay Time (in seconds)
Defines the amount of time the system must be running at or below the Enter Power Save Utilization threshold before the system would actually enter Idle Power Save state
- Exit Power Save Utilization threshold (percentage)
Defines the upper threshold of utilization. When the system reaches or goes above this threshold, it will be ready to exit Idle Power Save state.
- Exit Power Save Delay Time (in seconds)
Defines the amount of time the system must be running at or above the Exit Power Save Utilization threshold before the system would actually exit Idle Power Save state
When the system utilization drops below the "Enter Power Save Utilization threshold" for "Enter Power Save Delay Time" seconds, the system enters idle mode (reduced power / performance).
When the system utilization goes above the "Exit Power Save Utilization threshold" for "Exit Power Save Delay Time" seconds, the system switches back to active mode. (increased performance / power)
Documents discussing implementation / usage of Idle Power Save / EnergyStar functionality:
IBM White Paper: IBM EnergyScale for POWER9 Processor-Based Systems (see PowerVM Specific Features)
Intel Whitepaper: ENERGY START System Implementation (PDF)
Microsoft: SYSTEM_POWER_POLICY (see POWER_ACTION_POLICY)
The power mode would define, at a high level, the algorithm in which the processor frequency is adjusted to control how much power is being consumed. This allows a system to be configured based on the power or performance needs of its users. The mode should be able to be written prior to powering on as well as being changed while the system is running.
Example power modes:
Maximum Performance - processor will always be running at highest speeds possible (power usage not considered)
This mode would be used for workloads where performance is the top priority.
Dynamic Performance / On Demand - processor will run at the highest speeds until the utilization drops (power saved when system not busy)
This mode is a compromise giving maximum performance when busy, while still saving power when the system is not under heavy load.
Power Save - processor will run at a reduced speed to save power
This could be used for systems running batch jobs or off-shit applications not requiring high performance
Linux systems refer to the power mode as a "governor"
Documents discussing implementation / usage of power modes / governors
Arch Linux: CPU Frequency Scaling
Intel White Paper: Power Management in Intel Architecture Servers
IBM White Paper: IBM EnergyScale for POWER9 Processor-Based Systems (see PowerVM Specific Features)
2. We would like to add additional parameters related to support Idle Power Save. This allows the system owner to define when a system should be considered idle vs active. When a system is idle, the processor frequency can be automatically reduced to lower power consumption and then restore performance when the system becomes active again. This can be used to ensure systems can meet EnergyStar compliance.
The following parameters would be desired:
- Idle Power Saver Enabled / Disabled
Defines if this feature is enabled or not
- Enter Power Save Utilization threshold (percentage)
Defines the lower threshold of utilization. When the system drops down to or below this threshold, it will be ready to go to Idle Power Save state.
- Enter Power Save Delay Time (in seconds)
Defines the amount of time the system must be running at or below the Enter Power Save Utilization threshold before the system would actually enter Idle Power Save state
- Exit Power Save Utilization threshold (percentage)
Defines the upper threshold of utilization. When the system reaches or goes above this threshold, it will be ready to exit Idle Power Save state.
- Exit Power Save Delay Time (in seconds)
Defines the amount of time the system must be running at or above the Exit Power Save Utilization threshold before the system would actually exit Idle Power Save state
When the system utilization drops below the "Enter Power Save Utilization threshold" for "Enter Power Save Delay Time" seconds, the system enters idle mode (reduced power / performance).
When the system utilization goes above the "Exit Power Save Utilization threshold" for "Exit Power Save Delay Time" seconds, the system switches back to active mode. (increased performance / power)
Documents discussing implementation / usage of Idle Power Save / EnergyStar functionality:
IBM White Paper: IBM EnergyScale for POWER9 Processor-Based Systems (see PowerVM Specific Features)
Intel Whitepaper: ENERGY START System Implementation (PDF)
Microsoft: SYSTEM_POWER_POLICY (see POWER_ACTION_POLICY)