Dissecting the CPU-Memory Relationship in Garbage Collection (OpenJDK 26)
Summary
OpenJDK 26 introduces telemetry to quantify GC CPU overhead, challenging the view that GC pauses alone measure system efficiency. It proposes -Xlog:cpu and MemoryMXBean.getTotalGcCpuTime as explicit cost metrics and discusses explicit, implicit, and microarchitectural GC costs. The article uses DaCapo xalan and Spring benchmarks to show how memory constraints alter GC CPU usage and why accurate instrumentation matters for capacity planning.