Memory Read Credit Control for Speculative Latency Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Read latency in memory systems degrades system performance, and existing methods to reduce this latency are inefficient.

Innovation Solution

A memory system utilizing a buffer and speculative read technique to predict future data needs, adjusting credit quantities based on speculative read hits and misses to optimize memory access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If speculative read requests are transmitted to reduce read latency, then read latency is reduced, but unnecessary memory operations increase

Engineering Contradiction:

Improveread latencyVSAvoidunnecessary memory operations

Core Design Contradiction:

Loss of timeVSLoss of energy

Solution Approach 1:

The controller implements a feedback mechanism by tracking speculative read hits and misses, adjusting the total quantity of credits based on hit ratios. When hit ratio exceeds a threshold, total credits are increased; when below threshold, total credits are decreased. This feedback loop optimizes speculative read behavior to balance latency reduction with energy efficiency.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the quantity of credits available for speculative reads based on real-time performance metrics. The controller modifies the total quantity of credits during operation based on hit/miss patterns, making the speculative read capacity adaptive rather than fixed, thereby optimizing the trade-off between reduced latency and minimized unnecessary operations.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If quantity of credits is increased to handle more speculative reads, then read latency is reduced, but device complexity increases

Engineering Contradiction:

Improveread latencyVSAvoidcredit management complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The controller autonomously manages credit allocation and adjustment without external intervention. It automatically tracks speculative read outcomes, calculates hit ratios, and adjusts total credits based on predetermined thresholds, making the system self-regulating and reducing the need for complex external credit management mechanisms.

Inventive Principle:

Principle #25Self-service

3Loss of energy

If speculative read requests are discarded to reduce unnecessary operations, then energy consumption is reduced, but read latency increases

Engineering Contradiction:

Improveunnecessary memory operationsVSAvoidread latency

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

The system changes operational parameters (quantity of credits) based on performance conditions. By adjusting the total quantity of credits according to hit ratios and threshold comparisons, the system adapts the level of speculative read activity to balance energy consumption and latency requirements dynamically.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260064279A1Memory system and operating method of memory system

Publication Date: 2026.03.05 SK HYNIX INC

AI summary

A memory system includes a memory sub-system, and a controller configured to transmit, to the memory sub-system, a read command corresponding to a speculative read request according to a quantity of remaining credits, receive, from the memory sub-system, read data corresponding to the speculative read request, and adjust a total quantity of credits and the quantity of remaining credits according to whether the read data is a speculative read hit.