Processor Frequency Control via Interrupt Rate Monitoring

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Solution Overview

Problem

In computer processors, handling interrupts can lead to reduced performance due to frequency reductions during low processor utilization, even if the interrupt rate is high, causing inefficiencies in power management.

Innovation Solution

Performance counters are used to determine interrupt rate metrics, and a power control circuit adjusts the operating frequency of processing engines to maintain or increase frequency when interrupt rates exceed thresholds, preventing frequency reductions during high interrupt activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If processor frequency is reduced during low processor utilization periods to save power, then power consumption is reduced, but interrupt handling performance deteriorates when interrupt rate is high

Engineering Contradiction:
Improvepower consumptionVSAvoidinterrupt handling performance
Core Design Contradiction:
Use of energy by stationary objectVSProductivity

Solution Approach 1:

The processor frequency is dynamically adjusted based on real-time monitoring of both processor utilization and interrupt rates. The system transitions from static frequency control to dynamic frequency modulation, where frequency changes are made responsive to changing system conditions. When interrupt rates exceed thresholds during low utilization periods, the frequency is maintained or increased despite general power-saving intentions, resolving the contradiction between power consumption and interrupt handling performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by continuously monitoring interrupt rates and processor utilization metrics. Performance counters track interrupt handling activity, and this information feeds back to the frequency control mechanism. Based on this feedback, the system adjusts processor frequency to ensure that high interrupt rates trigger frequency increases or maintenance, preventing the performance degradation that would otherwise occur during low utilization periods.

Inventive Principle:
Principle #23Feedback

2Productivity

If processor frequency is increased to handle high interrupt rates, then interrupt handling performance is improved, but power consumption increases

Engineering Contradiction:
Improveinterrupt handling performanceVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The system changes the operating parameter (processor frequency) conditionally based on monitored performance metrics. Rather than maintaining a constant high frequency that would waste power during low interrupt periods, the system adjusts frequency parameters dynamically. When performance counters indicate high interrupt rates, the frequency parameter is increased or maintained; when interrupt rates are low, the frequency is reduced, thereby optimizing the balance between interrupt handling performance and power consumption.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If performance counters monitor interrupt rates to adjust frequency, then frequency control accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveinterrupt rate measurementVSAvoidcontrol circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The processor utilizes its own existing performance counters and monitoring infrastructure to track interrupt rates and utilization metrics. Rather than adding entirely new monitoring systems, the system leverages self-service capabilities already present in the processor architecture. This approach improves measurement precision for frequency control while minimizing the increase in device complexity by reusing existing hardware resources.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3646179B1Modifying processor frequency based on interrupt rate
Publication Date: 2023.10.25 INTEL CORP
  • EP3646179B1 patent drawingFigure 1
  • EP3646179B1 patent drawingFigure 2
  • EP3646179B1 patent drawingFigure 3

AI summary

A processor includes processing engines, at least one performance counter, and a power control circuit. The at least one performance counter is to determine at least one interrupt rate metric for a first processing engine. The power control circuit is to determine, using the at least one performance counter, whether the at least one interrupt rate metric has reached a first threshold while the first processing engine is operating at a first frequency level, and in response to a determination that the at least one interrupt rate metric has reached the first threshold while the first processing engine is operating at the first frequency level, increase an operating frequency of the first processing engine from the first frequency level to a second frequency level.