Memory System Power Management via Scrubbing Segmentation

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Solution Overview

Problem

Contemporary memory systems face power penalties due to scrubbing unused memory, which can impact performance and reliability, as they either experience significant delays or decreased error detection capabilities when scrubbing is slowed down.

Innovation Solution

Implementing memory mirroring to allocate unscrubbed memory to both mirrored and mirroring copies, allowing scrubbing only on used memory, and deallocating the other copy once it is determined error-free, thereby conserving power without compromising reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If memory scrubbing is performed on unused memory, then reliability is improved, but power consumption increases

Engineering Contradiction:

Improveerror detection capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments memory into used and unused portions, applying different scrubbing strategies to each. Only used memory is scrubbed continuously, while unused memory is allocated without scrubbing, thereby reducing power consumption while maintaining reliability for active data.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary scrubbing of unused memory before allocation to logical partitions. By scrubbing unused memory in advance and verifying its integrity, the system ensures reliability is maintained while avoiding continuous power-consuming scrubbing operations on unused memory.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If memory allocation includes scrubbing, then reliability is improved, but allocation performance deteriorates

Engineering Contradiction:

Improveerror detection capabilityVSAvoidallocation speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent performs scrubbing of unused memory in advance before allocation occurs. By pre-scrubbing and validating unused memory pools, the allocation process can proceed quickly without performing scrubbing operations at allocation time, thus maintaining both reliability and allocation performance.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If memory scrubbing rate is reduced, then power consumption decreases, but error detection capability deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidsoft error detection rate

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent segments memory management into continuous scrubbing of used memory and pre-allocation scrubbing of unused memory. This segmentation ensures that error detection capability is maintained for actively used memory through continuous scrubbing, while power is saved by not continuously scrubbing unused memory.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary scrubbing of unused memory at appropriate intervals before allocation. This preliminary action ensures that unused memory is validated for errors before being put into service, maintaining error detection capability without requiring continuous high-rate scrubbing that would consume excessive power.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10168936B2Memory system power management

Publication Date: 2019.01.01 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

An aspect includes a method for receiving a memory allocation request for a logical partition. Partition mirroring is enabled for the logical partition. Unscrubbed memory is allocated to both a first and a second copy of the logical partition, with the second copy of the logical partition mirroring the first copy of the logical partition. Scrubbing of the first and second copy of the logical partitions is initiated. Subsequent to initiating the scrubbing one of the first and second copy of the logical partition is selected and partition mirroring is disabled for the logical partition. The first copy of the logical partition is deallocated based on selecting the second copy of the logical partition. The second copy of the logical partition is deallocated based on selecting the first copy of the logical partition.