VM Timestamp Synchronization via Offset Adjustment

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Solution Overview

Problem

In virtualized environments, time drift between virtual machines (VMs) occurs due to differences in their virtual clock counters, leading to synchronization issues when generating and reconciling traces with timestamps.

Innovation Solution

The solution involves determining a time offset between the virtual clock counters of two VMs and adjusting the timestamps of traces generated by one VM to synchronize them with the other VM, using Precision Time Protocol (PTP) to calculate the time offset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If each virtual machine uses its own virtual clock counter independently, then each VM can maintain its own time accurately, but time drift occurs between VMs making trace reconciliation difficult

Engineering Contradiction:

Improvetimestamp accuracyVSAvoidtrace synchronization

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a hypervisor as an intermediary between virtual machines. The hypervisor manages virtual clock counters and provides timestamp adjustment mechanisms that mediate between individual VM timekeeping and system-wide synchronization requirements, allowing traces from multiple VMs to be reconciled accurately

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the timestamp parameter by introducing adjustment values that compensate for time drift. Instead of using raw virtual clock timestamps directly, the system modifies timestamps by adding or subtracting calculated adjustment values to align them with a reference time, resolving the synchronization issue while preserving individual VM time accuracy

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250085739A1Timestamp synchronization across virtual machines

Publication Date: 2025.03.13 GOOGLE LLC

AI summary

Timestamp synchronization may be performed by determining a time offset between a first virtual machine having a first virtual clock counter of a computing system and a second virtual machine having a second virtual clock counter of the computing system; and adjusting timestamps of traces with timestamps based on the second virtual clock counter according to the time offset.