Dual-mode processor pipeline sampling for idle time utilization

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Solution Overview

Problem

Contemporary pipeline sampling techniques are inefficient as they often result in a significant portion of sampled data being idle or inactive, leading to wasted sampling time and limited usable data for analysis, as only a subset of sampling time generates usable information when the pipeline is active.

Innovation Solution

Implementing a dual or multi-mode sampling system that gathers alternative data when the pipeline is idle, including overall system information relevant to pipeline performance but not dependent on pipeline activity, allowing for confirmation of system performance characteristics and analysis of additional characteristics that cannot be inferred from active pipeline data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If sampling is performed at periodic intervals regardless of pipeline activity, then sampling time is utilized consistently, but a significant portion of sampled data becomes idle or inactive when the pipeline is idle

Engineering Contradiction:
Improvesampling time utilizationVSAvoidusable data quality
Core Design Contradiction:
Loss of timeVSLoss of information

Solution Approach 1:

The sampling system dynamically adapts its behavior based on pipeline activity state. When the pipeline is active, the system samples pipeline data; when idle, it samples alternative system information. This dynamic adaptation resolves the contradiction by making sampling time productive regardless of pipeline state, eliminating wasted sampling opportunities while maintaining data quality.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter being sampled based on pipeline activity. Instead of always sampling pipeline data, the system switches between sampling pipeline data and alternative system information depending on the pipeline's operational state. This parameter change ensures that every sampling interval produces usable information, addressing both time utilization and data quality concerns.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If sampling time is kept within set limits to conserve processor resources, then processor overhead is controlled, but the amount of usable data collected is reduced

Engineering Contradiction:
Improvesampling efficiencyVSAvoidcomprehensive performance data
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The sampling system is designed to perform multiple functions within the same sampling infrastructure. By sampling both pipeline data and alternative system information (such as system bus activity, cache controller activity, or other processor components) using the same sampling circuitry and time intervals, the system maximizes data collection without increasing processor overhead or extending sampling time limits.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If only pipeline data is sampled, then sampling focus remains narrow and processing is simplified, but comprehensive system performance characteristics cannot be analyzed

Engineering Contradiction:
Improvesampling system complexityVSAvoidsystem performance insights
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The system introduces alternative system information as an intermediary data source that complements pipeline data. This intermediary information (such as system bus activity, cache controller status, or memory controller data) provides additional performance insights without requiring a complete redesign of the sampling system. The same sampling infrastructure that collects pipeline data also collects this intermediary information, achieving comprehensive analysis with minimal added complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS10176013B2Dual/multi-mode processor pipeline sampling
Publication Date: 2019.01.08 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US10176013B2 patent drawing
  • US10176013B2 patent drawing
  • US10176013B2 patent drawing

AI summary

Embodiments are directed to systems and methodologies for efficiently sampling data for analysis by a pipeline analysis algorithm. The amount of sampled data is maximized without increasing sampling overhead by sampling “non-pipeline activity” data if the subject pipeline is inactive during the sampling time. The non-pipeline activity data is selected to include overall system information that is relevant to the subject pipeline's performance but is not necessarily dependent on whether the subject pipeline is active. In some embodiments, the non-pipeline activity data allows for confirmation of a pipeline performance characteristic that must otherwise be inferred by the subsequent pipeline analysis algorithm from data sampled while the pipeline was active. In some embodiments, the non-pipeline activity data allows the pipeline analysis algorithm to analyze additional performance characteristics that cannot otherwise be inferred from the data sampled while the pipeline was active.