Memory Activation Indicator for Pipelined Processor Power Saving
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Solution Overview
Problem
Current pipelined processors face high power consumption due to unnecessary activation of both instruction and data caches during memory access operations, leading to inefficient energy usage.
Innovation Solution
A power-saving method is implemented in the pipelined processor, where a memory-activation indicator, such as a program counter or register file, determines whether to activate specific volatile memories like instruction caches or data caches based on content information, optimizing memory access stages and reducing redundant memory activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both instruction cache and data cache are activated during memory access operations, then memory access reliability is improved, but power consumption increases
Solution Approach 1:
The patent segments the cache activation process by introducing separate activation indicators for instruction cache and data cache. The memory activation indicator is divided into multiple bits, where each bit controls the activation of a specific cache level (e.g., L1 instruction cache, L2 instruction cache, L1 data cache, L2 data cache). This segmentation allows independent control of each cache's activation state, enabling the system to activate only the necessary cache(s) for a given memory access operation, thereby reducing power consumption while maintaining access reliability.
Solution Approach 2:
The patent implements dynamic cache activation control by making the activation state of each cache level variable rather than fixed. The memory activation indicator allows the system to dynamically adjust which cache levels are activated based on the specific memory access requirements. This dynamic approach enables the system to adapt to different access patterns (e.g., instruction fetch vs. data access) and activate only the necessary cache hierarchy levels, optimizing the trade-off between reliability and power consumption.
2Speed
If cache hierarchy is activated to reduce memory access latency, then access speed is improved, but power consumption increases
Solution Approach 1:
The patent applies segmentation to the cache hierarchy control by introducing separate activation indicators for different cache levels (L1 and L2 caches for both instructions and data). This allows the system to activate only the necessary cache levels based on access patterns, rather than keeping the entire hierarchy active. By segmenting the control, the system can selectively enable faster cache access when needed while avoiding the power cost of maintaining all cache levels active simultaneously.
Solution Approach 2:
The patent implements partial action by activating only the necessary portion of the cache hierarchy rather than the entire hierarchy. The memory activation indicator allows selective activation of individual cache levels (e.g., activating only L1 cache for a simple data access, or activating L2 cache only when L1 miss occurs). This partial activation approach reduces power consumption compared to excessive action (activating all caches), while still providing fast access when needed.
3Reliability
If redundant memory activation is performed to ensure data availability, then data access reliability is improved, but energy efficiency deteriorates
Solution Approach 1:
The patent segments the redundancy control by introducing selective activation indicators that allow the system to activate only the necessary cache levels based on the specific memory access operation. Instead of activating all caches redundantly, the system can activate only the relevant cache(s) for a given access pattern (e.g., activating L1 data cache for data loads, or activating instruction caches for instruction fetches). This segmented approach maintains data availability reliability while avoiding the energy waste of redundant activation.
Solution Approach 2:
The patent implements self-service by allowing the memory activation indicator to automatically determine which cache levels should be activated based on the memory access characteristics. The indicator uses the memory access information (such as address space, access type) to self-determine the optimal activation pattern without requiring external intervention. This self-service mechanism ensures reliable data access by activating appropriate caches while avoiding energy waste from unnecessary redundancy.
Data Source
AI summary
A pipelined processor for carrying out pipeline processing of instructions, which undergo a plurality of stages, is provided. The pipelined processor includes: a memory-activation indicator and a memory controller. The memory-activation indicator stores content information that indicates whether to activate a first volatile memory and/or a second volatile memory while performing a current instruction. The memory controller is arranged for controlling activation of the first volatile memory and/or the second volatile memory in a specific stage of the plurality of stages of the current instruction according to the content information stored in the memory-activation indicator.