Shenandoah is an advanced garbage collector (GC) algorithm designed for low-pause time in large heaps. It is available in OpenJDK and uses concurrent phases to minimize pauses during garbage collection.
In this blog post, we will explore two important features of Shenandoah GC: Incremental Mode and Concurrent Evacuation.
Table of Contents
What is Shenandoah GC?
Shenandoah GC is a garbage collector algorithm developed by Red Hat. It is designed to minimize pause times and support large heaps in Java applications.
Traditionally, garbage collection pauses are known to cause latency spikes in applications, impacting the user experience. Shenandoah GC aims to address this by providing concurrent and parallel phases of garbage collection.
Incremental Mode
Incremental mode is a feature in Shenandoah GC that allows the garbage collector to divide the collection cycle into smaller chunks or increments. Instead of performing a single long pause for garbage collection, incremental mode allows the GC to pause in shorter intervals, minimizing the impact on the application’s responsiveness.
During each increment, the GC collects a subset of the heap, reducing the pause time required for each collection. This feature ensures that the pause duration remains consistent and predictable, thereby maintaining low latency and smoother application performance.
Incremental mode is useful when working with large heaps, as it allows the GC to perform collection cycles without disrupting the application’s normal execution for an extended period of time.
Concurrent Evacuation
Concurrent evacuation is another feature provided by Shenandoah GC. It enables the GC to evacuate live objects concurrently with the running application, reducing pause times even further.
During normal operation, Shenandoah GC determines which objects are garbage and marks them accordingly. However, instead of waiting for a pause to evacuate them, concurrent evacuation allows the GC to move live objects to free up memory while the application is still running.
By performing concurrent evacuation, Shenandoah GC can avoid lengthening pause times and ensure that garbage collection does not impact the application’s performance significantly.
Conclusion
The incremental mode and concurrent evacuation features of Shenandoah GC make it a powerful solution for reducing garbage collection pause times. By dividing the collection into smaller increments and evacuating live objects concurrently, Shenandoah GC ensures low latency and smoother application performance.
If you’re working with large Java applications that require minimal pause times for garbage collection, consider exploring Shenandoah GC as a potential solution.
#gc #garbagecollection