Claude
e83c9949d8
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
45 lines
3.7 KiB
Plaintext
45 lines
3.7 KiB
Plaintext
== JDK 25: OpenJDK Runtime Environment Temurin-25.0.4.1+1 (build 25.0.4.1+1-LTS)
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default (this machine: 2 CPUs) -> compact=false collector=UseG1GC MaxHeapSize=1498MB
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-XX:+UseCompactObjectHeaders -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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-XX:-UseCompactObjectHeaders -> compact=false collector=UseG1GC MaxHeapSize=1498MB
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== JDK 26: OpenJDK Runtime Environment Temurin-26.0.2.1+1 (build 26.0.2.1+1)
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default (this machine: 2 CPUs) -> compact=false collector=UseG1GC MaxHeapSize=1498MB
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-XX:+UseCompactObjectHeaders -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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-XX:-UseCompactObjectHeaders -> compact=false collector=UseG1GC MaxHeapSize=1498MB
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== JDK 27: OpenJDK Runtime Environment Temurin-27+35 (build 27+35)
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default (this machine: 2 CPUs) -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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-XX:+UseCompactObjectHeaders -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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-XX:-UseCompactObjectHeaders -> compact=false collector=UseG1GC MaxHeapSize=1498MB
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== The same JDKs in a container: 1 GB memory limit, 1 CPU (a cgroup, set the way Docker sets it)
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JDK 25, 1 GB, 1 CPU -> compact=false collector=UseSerialGC MaxHeapSize=256MB
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JDK 25, 1 GB, 1 CPU, MaxRAMPercentage=75 -> compact=false collector=UseSerialGC MaxHeapSize=768MB
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JDK 26, 1 GB, 1 CPU -> compact=false collector=UseSerialGC MaxHeapSize=256MB
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JDK 26, 1 GB, 1 CPU, MaxRAMPercentage=75 -> compact=false collector=UseSerialGC MaxHeapSize=768MB
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JDK 27, 1 GB, 1 CPU -> compact=true collector=UseG1GC MaxHeapSize=256MB
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JDK 27, 1 GB, 1 CPU, MaxRAMPercentage=75 -> compact=true collector=UseG1GC MaxHeapSize=768MB
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== 1 GB, 2 CPUs
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JDK 26, 1 GB, 2 CPUs -> compact=false collector=UseSerialGC MaxHeapSize=256MB
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JDK 27, 1 GB, 2 CPUs -> compact=true collector=UseG1GC MaxHeapSize=256MB
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== -XX:MaxRAM: the flag many people used to fake a container limit
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JDK 26 -XX:MaxRAM=1g -> compact=false collector=UseG1GC MaxHeapSize=256MB
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JVM says: OpenJDK 64-Bit Server VM warning: Option MaxRAM was deprecated in version 26.0 and will likely be removed in a future release.
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JDK 27 -XX:MaxRAM=1g -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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JVM says: OpenJDK 64-Bit Server VM warning: Ignoring option MaxRAM; support was removed in 27.0
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== Compact headers with each collector on JDK 27
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JDK 27 -XX:+UseG1GC -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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JDK 27 -XX:+UseParallelGC -> compact=true collector=UseParallelGC MaxHeapSize=1498MB
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JDK 27 -XX:+UseSerialGC -> compact=true collector=UseSerialGC MaxHeapSize=1498MB
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JDK 27 -XX:+UseZGC -> compact=true collector=UseZGC MaxHeapSize=1498MB
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== Compressed pointers on JDK 27
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JDK 27 -XX:-UseCompressedClassPointers -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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JVM says: OpenJDK 64-Bit Server VM warning: Ignoring option UseCompressedClassPointers; support was removed in 27.0
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JDK 27 -XX:-UseCompressedOops -> compact=true collector=UseG1GC MaxHeapSize=1498MB
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JDK 27 -Xmx32g (a large explicit heap) -> compact=true collector=UseG1GC MaxHeapSize=32768MB
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