VM Live Migration Using Sleep-Intercepted VCPU Reallocation
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Solution Overview
Problem
During live migration of virtual machines, the additional occupation of CPU resources by migration threads degrades the performance of the virtual machine, especially when all CPUs on the host are allocated to the VM.
Innovation Solution
An intercept switch is configured to intercept sleep instructions, allowing idle VCPU threads to transition to a sleep state on the host side, freeing up CPU resources for live migration, while ensuring the VCPU threads can be woken up efficiently using timers or interrupts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If migration threads are initiated to continuously copy memory data of the VM to a destination host, then live migration can be performed, but redundant CPU resources are additionally occupied to run the migration threads
Solution Approach 1:
The patent extracts the migration thread execution from the client side (VM) to the host side. By intercepting sleep instructions and exiting VCPU threads to the host, the migration operation is separated from the VM's CPU resource management, allowing migration to proceed without consuming VM's CPU resources.
Solution Approach 2:
The patent introduces an intercept switch as an intermediary mechanism between the VM and host. This switch intercepts sleep instructions and facilitates the transition of VCPU threads to the host side, enabling resource allocation without direct conflict between migration and VM execution.
2Productivity
If all CPUs on the host are allocated to the VM for use, then maximum VM performance is achieved, but no CPU resources remain available for live migration operations
Solution Approach 1:
The patent implements dynamic CPU resource allocation by enabling the host to temporarily acquire VCPU threads during migration operations. The intercept switch dynamically changes state based on migration needs, allowing full CPU allocation to VM during normal operation and temporary reclamation during migration.
Solution Approach 2:
The patent changes the operational parameters of VCPU threads by transitioning them between client-side and host-side execution contexts. By modifying the execution location parameter of VCPU threads through instruction interception, the system achieves flexible resource allocation without permanent performance degradation.
Data Source
AI summary
A method comprises: adjusting, in response to a live migration operation for a virtual machine at a client side, an intercept switch for intercepting a sleep instruction to ON state, wherein the sleep instruction is used for switching a virtual central processor (VCPU) thread running in the virtual machine to a sleep state at the client side; intercepting, in response to receiving the sleep instruction for a target VCPU thread, the sleep instruction, wherein the target VCPU thread is of a plurality of VCPU threads running in the virtual machine; exiting the target VCPU thread from the client side to a host side, switching the target VCPU thread to the sleep state at the host side, and controlling a live migration thread by a scheduler at the host side to occupy CPU resources of the target VCPU thread to execute the live migration of the virtual machine.