Runtimes & Languages
JVM Garbage Collector Shootout: ZGC vs Shenandoah vs G1
Analyze JVM Garbage Collector latency spikes by comparing ZGC, Shenandoah, and G1GC on heavy 64GB heap workloads.
Test Environment
CPUIntel Xeon Gold 6230
RAM128GB
OSRHEL 9
ToolSPECjbb2015
Metrics Comparison
Max Pause Time
Unit: msZGC
0.8★
Shenandoah
1.5
G1GC
150.0
Detailed Analysis
ZGC and Shenandoah practically eliminate stop-the-world pauses (<1ms), vastly outperforming G1 for latency-sensitive applications.
ZGC performs all expensive work (marking, relocation, remapping) concurrently with application threads using colored pointers.
Evacuation
Moving surviving objects
Bottleneck: G1 pauses application threads during evacuation.
Architectural Recommendations
- Enable ZGC (-XX:+UseZGC) for web servers and trading systems
- G1 is still good for batch processing
Frequently Asked Questions
What is the trade-off with ZGC?
Slightly lower overall throughput and higher CPU usage compared to G1.