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
2.4 KiB
Bash
Executable File
45 lines
2.4 KiB
Bash
Executable File
#!/usr/bin/env bash
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# JEP 523 in a small container: 1 CPU, 1 GB. JDK 26 picks Serial here, JDK 27 picks G1. What does the app
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# cost under each collector, and what does the JVM say it spends outside the heap (Native Memory Tracking)?
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# usage: one-cpu.sh [N products] [runs]
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source "$(dirname "$0")/lib.sh"
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N="${1:-2000000}"; RUNS="${2:-3}"
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TMP="$(mktemp -d)"
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MB=$((1024*1024))
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export NMT=1 CG_MEM=$((1024*MB)) CG_CPUS=1
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nmt() { # file -> "GC committed KB|Total committed KB"
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local gc tot
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gc=$(awk '/^- *GC \(reserved/ {gsub(/[^0-9=]/," "); n=split($0,a,"="); print a[3]+0; exit}' "$1")
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tot=$(awk '/^Total: reserved/ {gsub(/[^0-9=]/," "); n=split($0,a,"="); print a[3]+0; exit}' "$1")
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echo "$gc|$tot"
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}
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row() { # label jdk flags...
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local label="$1" jh="$2"; shift 2
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local st=() live=() rss=() gcn=() gcms=() ld=() gck=() totk=() coll="" cpus=""
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for r in $(seq 1 "$RUNS"); do
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d="$TMP/$label-$r"
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run_app "$jh" "$N" "$d" -XX:MaxRAMPercentage=50 "$@" >/dev/null 2>&1 || { echo "$label run $r FAILED: $(cat "$d/outcome.txt")"; return; }
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coll=$(kv "$d/memory.txt" collectors); cpus=$(kv "$d/memory.txt" availableProcessors)
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st+=("$(grep -o '[0-9.]*' "$d/startup.txt" | tail -1)")
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live+=("$(kv "$d/memory.txt" heapLiveAfterGcMB)"); rss+=("$(kv "$d/memory.txt" rssMB)")
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gcn+=("$(kv "$d/load.txt" gcCountDuringLoad)"); gcms+=("$(kv "$d/load.txt" gcMillisDuringLoad)")
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ld+=("$(kv "$d/load.txt" loadMillis)")
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IFS='|' read -r g t <<<"$(nmt "$d/nmt.txt")"; gck+=("$g"); totk+=("$t")
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done
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m() { printf '%s\n' "$@" | median; }
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printf '%s\n collectors=%s cpus=%s\n' "== $label" "$coll" "$cpus"
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printf ' startup=%ss live=%sMB rss=%sMB loadMillis=%s gcDuringLoad=%s (%sms)\n' \
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"$(m "${st[@]}")" "$(m "${live[@]}")" "$(m "${rss[@]}")" "$(m "${ld[@]}")" "$(m "${gcn[@]}")" "$(m "${gcms[@]}")"
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printf ' NMT: GC committed=%s KB Total committed=%s KB\n\n' "$(m "${gck[@]}")" "$(m "${totk[@]}")"
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}
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echo "# $N products, container = 1 GB / 1 CPU (cgroup), -XX:MaxRAMPercentage=50 (512 MB heap), NMT summary on, medians of $RUNS runs"
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row "jdk26-default (the JVM chose)" "$JDK26"
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row "jdk26 -XX:+UseG1GC" "$JDK26" -XX:+UseG1GC
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row "jdk27-default (the JVM chose)" "$JDK27"
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row "jdk27 -XX:+UseSerialGC" "$JDK27" -XX:+UseSerialGC
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row "jdk27 -XX:+UseSerialGC, compact off" "$JDK27" -XX:+UseSerialGC -XX:-UseCompactObjectHeaders
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rm -rf "$TMP"
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