Local Power Gating for Processor Leakage Reduction
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Solution Overview
Problem
Conventional power management techniques for integrated circuits, such as power gating, fail to optimize power consumption due to high leakage current losses, especially in underutilized core areas, leading to suboptimal energy efficiency.
Innovation Solution
Dynamic local power gating (LPG) is implemented, allowing selective power control of specific domains within a processor core based on usage, using embedded and local power gates to isolate and manage power planes, thereby minimizing performance impact and reducing leakage power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power gating is used to disable entire cores, then power consumption is reduced, but leakage current losses remain high and power saving is suboptimal
Solution Approach 1:
The processor core is divided into multiple functional domains (e.g., L1 cache, L2 cache, execution units, branch prediction units) with separate power planes. Each domain can be independently powered on or off based on its usage, allowing selective power gating at a granular level rather than disabling the entire core. This segmentation enables precise control over leakage current in each domain.
Solution Approach 2:
Different power management strategies are applied to different domains within the core based on their specific usage patterns and criticality. High-performance domains remain powered on while low-activity domains are powered off, creating localized power optimization without affecting overall core functionality. Each domain receives customized power control tailored to its operational requirements.
2Loss of energy
If entire cores are deactivated to save power, then leakage power is reduced, but performance impact is significant when core areas are needed
Solution Approach 1:
The power state of each domain is dynamically adjusted based on real-time usage detection. When a domain is detected as unused, its power is reduced or cut off. When usage is detected, power is restored to that domain while other domains maintain their current state. This dynamic approach allows the system to adapt power consumption to actual operational needs, maintaining performance where required while saving power where unnecessary.
3Loss of energy
If selective power control of specific domains is implemented, then leakage power is minimized, but device complexity increases due to embedded power gates and isolated power planes
Solution Approach 1:
The embedded power gates and isolated power plane infrastructure serve multiple functions: they enable selective power gating, provide leakage current control, support dynamic power management, and allow for future expansion of power management capabilities. This multi-functional design justifies the added complexity by delivering comprehensive power optimization across various operational scenarios.
4Use of energy by moving object
If conventional power gating disables entire cores, then power consumption decreases, but energy efficiency remains suboptimal due to high leakage current
Solution Approach 1:
Instead of applying full power gating to entire cores, the system applies partial power gating only to the specific domains that are currently unused. This partial action approach avoids the excessive power savings of complete core shutdown while eliminating the leakage current from inactive domains, achieving optimal energy efficiency without unnecessary performance loss.
Data Source
AI summary
In an embodiment, the present invention includes an execution unit to execute instructions of a first type, a local power gate circuit coupled to the execution unit to power gate the execution unit while a second execution unit is to execute instructions of a second type, and a controller coupled to the local power gate circuit to cause it to power gate the execution unit when an instruction stream does not include the first type of instructions. Other embodiments are described and claimed.