Dynamic Scan Rate Adjustment for VM Memory Page Migration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In virtual machine environments, the process of migrating memory pages from a source machine to a destination machine can be inefficient due to retransmission of modified pages, leading to wasted time, increased computational overhead, and unnecessary network bandwidth consumption.

Innovation Solution

A method is introduced where the activity level of each memory page is classified, and only the 'cold' pages are initially migrated, with subsequent passes focusing on 'frigid' and 'warm' pages, while dynamically adjusting the scanning time interval based on transmission progress to optimize the migration process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If memory pages are transmitted during VM migration, then data transfer is completed, but retransmission occurs when pages are modified, wasting time and network bandwidth

Engineering Contradiction:
Improvemigration efficiencyVSAvoidretransmission time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary classification of memory pages into activity levels (cold, warm, hot) before migration begins. By identifying and transmitting cold pages first, the system reduces the likelihood of retransmission since these pages are less likely to be modified during the migration process, thereby saving time and network resources.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the scanning rate for classifying memory pages based on migration progress. The scanning rate increases as migration progresses, allowing the system to adapt to changing memory access patterns and optimize the classification process in real-time, reducing unnecessary reclassifications and improving overall efficiency.

Inventive Principle:
Principle #15Dynamics

2Productivity

If memory pages are classified by activity level, then retransmissions are reduced, but classification process consumes computational resources

Engineering Contradiction:
Improvemigration efficiencyVSAvoidcomputational overhead
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

Instead of continuously monitoring all memory pages with high precision, the system applies partial classification by focusing on different activity levels at different stages. Cold pages are classified and transmitted first with lower scanning frequency, while only pages requiring higher precision classification are processed later, reducing overall computational overhead while maintaining migration efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The scanning rate for memory page classification is dynamically adjusted based on migration progress and page activity levels. The system uses lower scanning rates for cold pages and higher scanning rates only when necessary, optimizing the balance between classification accuracy and computational resource consumption.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If scanning rate for memory classification is increased, then classification accuracy improves, but processing time increases

Engineering Contradiction:
Improveactivity level classification accuracyVSAvoidclassification time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The scanning rate is dynamically adjusted during the migration process based on current conditions. The system starts with lower scanning rates for initial classification and increases the rate only when necessary, optimizing the balance between classification accuracy and processing time throughout the migration lifecycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary classification with moderate scanning rates to identify cold pages for initial transmission. Only after this preliminary action does the system increase scanning rates for more precise classification of remaining pages, thereby reducing overall time while maintaining necessary accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8832390B1Online classification of memory pages based on activity level using dynamically adjustable scan rates
Publication Date: 2014.09.09 VMWARE INC
  • US8832390B1 patent drawing
  • US8832390B1 patent drawing
  • US8832390B1 patent drawing

AI summary

Activity level of memory pages is repeatedly classified in a virtual machine environment, so that live VM migration can be carried out more efficiently. The time intervals upon which the activity level of the memory pages are repeatedly classified can be dynamically adjusted to better align its performance with the live VM migration process.