asmhatreandClaude Sonnet 5
f59c1de96d
Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01B38FGKKam5SCGgwgduVAh3
50 lines
2.1 KiB
Bash
Executable File
50 lines
2.1 KiB
Bash
Executable File
#!/usr/bin/env bash
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# JEP 523 in a real container: what does the JVM pick when nobody asks for a collector?
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# Runs GcReport in Docker with 1 CPU and 2 CPUs, on the JDK 26 and JDK 27 images.
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# ./scripts/g1-default.sh -> docs/output/01-g1-default-1cpu-vs-2cpu.txt
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# docs/output/02-g1-default-memory.txt
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set -euo pipefail
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source "$(dirname "$0")/env.sh"
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BUILD="$ROOT/build/g1"; rm -rf "$BUILD"; mkdir -p "$BUILD"
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"$JDK27/bin/javac" --release 26 -d "$BUILD" "$ROOT"/g1-container/src/*.java # one class file set runs on both JDKs
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run() { # image label docker-args... -- java-args...
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local img="$1" label="$2"; shift 2
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echo "\$ docker run --rm $* $img java -cp /app GcReport"
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docker run --rm "$@" -v "$BUILD:/app:ro" "$img" java -cp /app GcReport
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echo
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}
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{
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echo "# JEP 523: which collector does the JVM pick when you do not choose one?"
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echo "# Same class files, same vendor (Amazon Corretto), same 2 GB memory limit. Only the JDK version and the CPU limit change."
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echo
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for cpus in 1 2; do
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for img in "$IMG26" "$IMG27"; do
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echo "=== $img --cpus=$cpus --memory=2g"
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run "$img" x --cpus=$cpus --memory=2g
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done
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done
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} > "$OUT/01-g1-default-1cpu-vs-2cpu.txt" 2>&1
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{
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echo "# The other half of the old rule: memory. The old heuristic wanted at least 2 CPUs AND about 1792 MB."
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echo "# With 2 CPUs the CPU half of the rule is satisfied, so only the memory limit differs between these runs."
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echo
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for mem in 1g 2g; do
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for img in "$IMG26" "$IMG27"; do
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echo "=== $img --cpus=2 --memory=$mem"
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run "$img" x --cpus=2 --memory=$mem
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done
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done
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} > "$OUT/02-g1-default-memory.txt" 2>&1
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{
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echo "# The opt-out still works on 27: an explicit choice always wins over the JVM's."
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echo
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echo "=== $IMG27 --cpus=1 --memory=2g -XX:+UseSerialGC"
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echo "\$ docker run --rm --cpus=1 --memory=2g $IMG27 java -XX:+UseSerialGC -cp /app GcReport"
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docker run --rm --cpus=1 --memory=2g -v "$BUILD:/app:ro" "$IMG27" java -XX:+UseSerialGC -cp /app GcReport
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} > "$OUT/03-g1-default-optout.txt" 2>&1
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echo "wrote 01-, 02-, 03- transcripts to $OUT"
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