Add jdk27-memory: compact object headers and G1-everywhere on a Spring Boot service

Spring Boot 4.1.1 catalog service measured on JDK 25, 26 and 27: live heap 320 MB to 273 MB with compact headers, per-class bytes per instance, container-sizing sweeps with real cgroup limits, 1-CPU Serial vs G1 with Native Memory Tracking, removed flags (MaxRAM, UseCompressedClassPointers), and a kernel OOM-kill check. Outputs in jdk27-memory/output. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01TF9JWFvJSNm6HVzswzZU5a
2026-09-24 15:09:55 +00:00
parent e189da79ba
commit e83c9949d8
29 changed files with 1041 additions and 0 deletions
@@ -0,0 +1,12 @@
+== bytes per instance (= #bytes / #instances) from jcmd GC.class_histogram after loading 2,000,000 products
+class                                    JDK 26 default JDK 27 default JDK 27 opt-out
+com.ankurm.memory.Product                          40.0           32.0           40.0
+java.util.HashMap$Node                             32.0           24.0           32.0
+java.lang.Long                                     24.0           16.0           24.0
+java.lang.String                                   24.0           24.0           24.0
+[B                                                 32.7           32.6           32.7
+
+== total bytes of those five classes
+jdk26-default    309088088 bytes (294.8 MB)
+jdk27-default    260853264 bytes (248.8 MB)
+jdk27-optout     309272896 bytes (294.9 MB)