Dynamic Memory Bandwidth Control via Power-Temperature Feedback
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Solution Overview
Problem
Conventional thermal management of DIMMs relies on static binary rules, limiting bandwidth to 5-10% when nearing maximum temperature, which is inefficient and does not dynamically adjust to varying power and temperature conditions, leading to suboptimal performance and increased costs due to the need for platform DIMM power meters.
Innovation Solution
Implementing a proportional integral (PI) control algorithm with nested loops that dynamically adjust bandwidth limits based on temperature and power readings from DIMMs, allowing for continuous modulation of power consumption and temperature management without the need for additional power meters, thereby optimizing bandwidth usage and reducing system costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If static binary rules are used to limit bandwidth when nearing maximum temperature, then thermal management is simplified, but bandwidth efficiency is significantly reduced
Solution Approach 1:
The patent transforms the static binary bandwidth limiting rule into a dynamic control system that continuously adjusts bandwidth limits based on real-time temperature and power readings. The memory controller monitors DIMM temperature and power consumption, then dynamically modulates bandwidth limits to maintain operation near but below thermal thresholds, maximizing bandwidth efficiency while ensuring thermal safety.
Solution Approach 2:
The patent implements a feedback control loop where the memory controller continuously polls temperature sensors and power meters on DIMMs, compares readings against thresholds, and adjusts bandwidth limits accordingly. This closed-loop feedback system enables adaptive thermal management that responds to actual operating conditions rather than relying on fixed binary rules.
2Reliability
If bandwidth is limited to 5-10% when nearing maximum temperature, then thermal safety is ensured, but system performance is severely degraded
Solution Approach 1:
Instead of applying extreme bandwidth limiting (5-10%) only when thermal thresholds are approached, the patent applies partial bandwidth modulation continuously based on how close the DIMM is to thermal limits. This allows the system to operate at high bandwidth levels when safe and apply only the necessary bandwidth reduction to maintain thermal safety, rather than defaulting to severe limitations.
Solution Approach 2:
The patent changes the control parameter from a static binary state (full bandwidth or 5-10% bandwidth) to a continuous range of bandwidth limits based on real-time temperature and power measurements. By dynamically adjusting the bandwidth limit parameter according to actual thermal conditions, the system maintains thermal safety while avoiding unnecessary performance degradation.
3Adaptability or versatility
If platform DIMM power meters are deployed for thermal management, then power-aware thermal control is achieved, but system cost increases
Solution Approach 1:
The patent enables DIMMs to self-report their power consumption and temperature status to the memory controller through integrated sensors and counters. The memory controller then autonomously makes bandwidth limiting decisions based on this self-reported data, eliminating the need for external platform power meters. The DIMM essentially serves its own thermal monitoring needs.
Solution Approach 2:
The patent uses the memory controller as an intermediary that aggregates thermal and power data from multiple DIMMs and makes centralized bandwidth limiting decisions. This intermediary approach allows sophisticated power-aware thermal management without requiring expensive power meters at the platform level, as the memory controller mediates between DIMM self-reporting and thermal management actions.
4Productivity
If dynamic bandwidth adjustment based on power and temperature is implemented, then bandwidth efficiency is improved, but control algorithm complexity increases
Solution Approach 1:
The patent segments the thermal management control into distinct functional components: temperature sensing, power measurement, threshold comparison, and bandwidth limit calculation. By dividing the control algorithm into these modular segments, the system achieves dynamic bandwidth adjustment while keeping each component relatively simple and maintainable.
Data Source
AI summary
A memory controller includes a sensor poller and a proportional integral controller (PIC) coupled to the sensor poller. The sensor poller is to obtain a temperature and a power of a memory module (MM) operated by the controller, and the PIC is to: dynamically set at least one bandwidth limit for the MM, based, at least in part, on a relationship between a temperature of the MM, a power of the MM and a bandwidth of the MM. The dynamically set bandwidth limit defines the power of the MM at which the MM operates for a predetermined temperature limit. A system includes a memory controller and a dual in-line memory module (DIMM) operated by it.