Virtual NIC Interrupt Affinity Binding for Cloud VM Interference

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Solution Overview

Problem

In a virtual machine environment, the lack of a fixed correspondence between physical and virtual CPUs for interrupt processing of a virtual network interface card leads to unpredictable interference between applications and virtual machines sharing a physical machine, necessitating precise control over interrupt processing to avoid interference.

Innovation Solution

Establishing consistent affinity binding relationships between virtual and physical interrupts and their corresponding CPUs, with the Host OS automatically scheduling physical interrupts based on CPU load to prevent interference and optimize resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If no fixed correspondence is established between physical and virtual CPUs for interrupt processing, then the system has high flexibility in CPU scheduling, but interrupt processing becomes unpredictable and causes interference between applications and virtual machines

Engineering Contradiction:
ImproveCPU scheduling flexibilityVSAvoidinterrupt processing predictability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic affinity binding where the correspondence between physical and virtual CPUs is not fixed but can be adjusted based on system conditions. The Host OS monitors CPU load and dynamically rebinds virtual interrupts to different virtual CPUs, allowing the system to adapt to changing workloads while maintaining predictable interrupt processing through controlled dynamic reconfiguration rather than static assignment

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the Host OS continuously monitors CPU utilization and interrupt processing performance. Based on this feedback, the system adjusts the affinity binding between virtual interrupts and virtual CPUs, optimizing interrupt handling while preventing interference between virtual machines. The feedback loop ensures that scheduling decisions are based on actual system state rather than predetermined configurations

Inventive Principle:
Principle #23Feedback

2Productivity

If multiple virtual machines share a physical machine without affinity binding control, then resource utilization is high, but interference occurs between adjacent virtual machines

Engineering Contradiction:
Improveresource utilizationVSAvoidinterference between virtual machines
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the interrupt handling responsibilities by establishing separate affinity binding relationships for each virtual machine's interrupts. The Host OS maintains distinct affinity binding configurations that isolate interrupt processing paths for different virtual machines, preventing cross-contamination while allowing efficient resource sharing. This segmentation is achieved through virtual interrupt assignment to specific virtual CPUs with controlled affinity to physical CPUs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The Host OS acts as an intermediary layer that mediates between physical interrupt sources and virtual machine processing. It implements affinity binding rules that control how physical interrupts are distributed to virtual CPUs, acting as a buffer that prevents direct interference between virtual machines while maintaining high resource utilization through intelligent scheduling and load balancing

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If affinity binding is strictly controlled between interrupts and CPUs, then interrupt processing predictability is improved, but CPU resource utilization decreases due to idle CPUs

Engineering Contradiction:
Improveinterrupt processing predictabilityVSAvoidCPU resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system implements dynamic affinity binding that adjusts the strictness of CPU-interrupt correspondence based on system conditions. When CPUs are idle or load is low, the system relaxes affinity constraints to improve utilization. When interference risks are detected or predictability is compromised, the system tightens affinity binding to ensure reliable interrupt processing. This dynamic adjustment resolves the contradiction between strict control and resource efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the affinity binding parameters dynamically based on system state. The affinity binding configuration is not a fixed parameter but can be modified by the Host OS according to CPU load, interrupt patterns, and interference detection. This parameter flexibility allows the system to maintain predictability when needed while optimizing resource utilization during low-interference periods

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3073373B1Method for interruption affinity binding of virtual network interface card, and computer device
Publication Date: 2021.08.25 HUAWEI TECH CO LTD
  • EP3073373B1 patent drawingFigure 1~2
  • EP3073373B1 patent drawingFigure 3
  • EP3073373B1 patent drawingFigure 4A

AI summary

The present invention discloses a method for affinity binding of interrupt of a virtual network interface card, and a computer device. The method includes: receiving a request message sent by an IaaS resource management system, where the request message carries an interrupt affinity policy parameter of a virtual network interface card; performing one-to-one correspondence affinity binding between multiple virtual central processing units VCPUs and multiple physical central processing units PCPUs; performing affinity binding between a virtual interrupt of the virtual network interface card and a VCPU; and performing affinity binding between a physical interrupt of the virtual network interface card and a corresponding PCPU according to the affinity policy parameter.