Multi-Level Conditional Prediction for Random Read Commands

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Solution Overview

Problem

Data storage devices face inefficiencies in random read scenarios due to the inability to accurately predict and prefetch data, leading to reduced input-output operations per second (IOPS) and throughput performance.

Innovation Solution

A multi-level conditional prediction method is implemented in data storage devices, using a combination of machine-learning and statistical-based models, along with a history-pattern-matcher, to predict future random read commands by identifying associated streams and patterns, allowing for pre-fetching of data from memory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a read look ahead mechanism is used to predict and pre-fetch data, then IOPS and throughput performance are improved, but prediction accuracy is insufficient leading to reduced effectiveness

Engineering Contradiction:
ImproveIOPSVSAvoidprediction accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the prediction task into two distinct levels: stream prediction (identifying which stream will be accessed next) and command prediction (identifying the specific read command within that stream). This segmentation allows each level to specialize and improve overall prediction accuracy by breaking down the complex prediction problem into manageable components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions by maintaining history buffers and pattern matchers that continuously learn and store access patterns before they are needed. The stream predictor and command predictor are pre-configured with historical data structures, enabling them to make accurate predictions without waiting for actual access patterns to emerge.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If simple prediction methods are used, then device complexity is reduced, but prediction accuracy and hit-rate decrease

Engineering Contradiction:
Improveprediction accuracyVSAvoidprediction mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent adds a temporal dimension to the prediction system by implementing multi-level history buffers that store access patterns over time. Instead of analyzing only current access states, the system examines historical access sequences across multiple time dimensions, enabling more accurate predictions without significantly increasing hardware complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The history-pattern-matcher serves as an intermediary component that bridges raw access history and prediction decisions. It processes historical access patterns and transforms them into actionable prediction data for both stream and command predictors, simplifying the overall system architecture while improving accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multi-level prediction is implemented, then hit-rate and prediction accuracy improve, but latency and processing overhead increase

Engineering Contradiction:
Improvehit-rateVSAvoidprediction latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary action by continuously maintaining updated history buffers and pattern matchers in the background during normal operation. Prediction data structures are pre-computed and ready, allowing the multi-level prediction to execute quickly when needed without causing significant latency during actual read operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The prediction system serves itself by using its own prediction outcomes to continuously refine and update its historical patterns. The history buffers automatically learn from actual access patterns, creating a self-improving system that reduces latency over time as prediction accuracy increases and fewer false predictions occur.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11983442B2Data storage device and method for multi-level conditional prediction of future random read commands
Publication Date: 2024.05.14 SANDISK TECHNOLOGIES LLC
  • US11983442B2 patent drawing
  • US11983442B2 patent drawing
  • US11983442B2 patent drawing

AI summary

A data storage device and method for multi-level conditional prediction of future random read commands are provided. In one embodiment, a data storage device is provided comprising a memory and a controller. The controller is configured to receive a random read command from a host, wherein the received random read command is associated with a stream; predict a next stream to be received from the host; and predict a next random read command to be received from the host based on the received random read command and the predicted next stream. Other embodiments are possible, and each of the embodiments can be used alone or together in combination.