In this blog post, we’ll explore how to effectively monitor GC logs and metrics when using the Shenandoah garbage collector (GC) in your Java applications. Shenandoah GC is a low-pause garbage collector designed to reduce GC pause times and make them predictable, which can greatly benefit applications with large heaps.
Table of Contents
- Introduction
- Enabling Shenandoah GC Logging
- Analyzing Shenandoah GC Logs
- Monitoring Shenandoah GC Metrics
- Conclusion
Introduction
Shenandoah GC is an advanced garbage collector that supports concurrent garbage collection with very low pause times. It achieves this by concurrently evacuating live objects from the regions being reclaimed, allowing it to operate concurrently with the application threads.
To ensure that Shenandoah GC is performing optimally and to troubleshoot any potential issues, it’s important to monitor the GC logs and metrics. These logs and metrics provide valuable insights into the GC behavior, allowing you to identify potential bottlenecks or areas for improvement.
Enabling Shenandoah GC Logging
To enable Shenandoah GC logging, you need to configure the appropriate JVM flags when starting your Java application. Here’s an example of the flags you can use:
-Xlog:gc+shenandoah=debug
This flag specifies that the GC logging should be enabled for Shenandoah GC with a debug level of verbosity. You can adjust the log level as per your requirements.
Analyzing Shenandoah GC Logs
Once you have enabled Shenandoah GC logging, the GC logs will provide detailed information about the garbage collection cycles. These logs include important metrics such as pause times, evacuation information, regions processed, and more.
To analyze the Shenandoah GC logs effectively, you can use tools like GCViewer or GC easy. These tools provide intuitive graphical representations of the logs, making it easier to identify patterns and potential areas for optimization.
Monitoring Shenandoah GC Metrics
Apart from analyzing the GC logs, it is also important to monitor Shenandoah GC metrics in real-time. This allows you to proactively detect any issues and take appropriate actions before they impact your application’s performance.
Some commonly monitored Shenandoah GC metrics include:
- Pause Time: The time taken by GC pauses, indicating the stop-the-world time for application threads. Lower pause times are desirable.
- Evacuation Rate: Rate at which live objects are evacuated from the reclaimed regions. Higher evacuation rates indicate better GC performance.
- Region Utilization: Percentage of regions utilized by live objects. Higher values indicate efficient memory allocation.
You can monitor these metrics using various monitoring tools like Prometheus and Grafana by exposing Shenandoah GC metrics through JMX or other monitoring endpoints.
Conclusion
Monitoring GC logs and metrics when using Shenandoah GC is crucial to understand the garbage collection behavior and ensure optimal performance. The logs provide detailed insights into GC cycles, while the metrics help you proactively identify and address any issues. By effectively monitoring and analyzing these logs and metrics, you can optimize your Java applications’ performance and reduce GC-related pauses.
#gc #monitoring