CodeOnCode

Sep 16, 2026 · Backend Development

G1 Young Gen Tuning: Why Fixing Size Backfires & How to Adapt

This article explains why fixing G1's young generation size with -Xmn or percentage flags often harms performance, and demonstrates how to tune young GC by analyzing pause targets, Eden sizing, TLAB/PLAB logs, and object promotion patterns to let G1's adaptive sizing balance throughput and latency.