Ankur Mhatre
958b401f0f
Adds spring-boot-startup-time/, the companion project for BLOG-618: a runnable Spring Boot 4.1.1 application on JDK 25 that installs BufferingApplicationStartup and FlightRecorderApplicationStartup behind a system property, and a /diag/startup endpoint that computes step self time -- the number /actuator/startup does not give you and the one that names the actual culprits. Captured under docs/output/: the step tree sorted both ways, the same startup as JFR events, a +5000-class experiment putting 0.11 ms per scanned class on the classpath scan tax, the silent truncation a 2048-step buffer performs, and JDK 25 AOT cache timings (6.93 s to 4.82 s). Post body and metadata live in post/. Moves the existing Actuator project into actuator-in-production/ so the repository holds one directory per article; the root README is now an index.
70 lines
2.9 KiB
Bash
Executable File
70 lines
2.9 KiB
Bash
Executable File
#!/usr/bin/env bash
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# Records the same startup as JFR events instead of an in-memory buffer, then reads the
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# recording with the JDK's own `jfr` tool -- no Mission Control, no extra dependency.
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set -uo pipefail
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source "$(dirname "$0")/env.sh"
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REC=/tmp/startup.jfr
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rm -f "$REC"
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"$(dirname "$0")/stop.sh"
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"$JAVA_HOME/bin/java" \
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-XX:StartFlightRecording=filename=$REC,settings=profile,dumponexit=true \
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-Dstartup.tracking=jfr -jar "$JAR" > /tmp/startup-app.log 2>&1 &
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PID=$!
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for _ in $(seq 1 180); do curl -fs -o /dev/null localhost:8080/actuator/health && break; sleep 0.5; done
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grep -h 'Started StartupDiagnosisApplication' /tmp/startup-app.log | sed 's/^.*: //'
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kill -TERM $PID 2>/dev/null; wait $PID 2>/dev/null
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sleep 2
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echo
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echo "=== jfr summary (Spring rows only) ==="
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"$JAVA_HOME/bin/jfr" summary "$REC" | head -3
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"$JAVA_HOME/bin/jfr" summary "$REC" | grep -i -E 'spring|Event Count|=====' | head -10
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echo
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echo "=== the event type, in full ==="
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"$JAVA_HOME/bin/jfr" metadata "$REC" | grep -A22 '@Name("org.springframework' | head -24
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echo
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echo "=== the selector matters: the event is named by its FQCN, not 'StartupEvent' ==="
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echo -n " --events StartupEvent -> "
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"$JAVA_HOME/bin/jfr" print --events StartupEvent --json "$REC" \
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| python3 -c "import sys,json;print(len(json.load(sys.stdin)['recording']['events']),'events')"
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echo -n " --events 'org.springframework.core.*' -> "
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"$JAVA_HOME/bin/jfr" print --events 'org.springframework.core.metrics.jfr.FlightRecorderStartupEvent' --json "$REC" \
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| python3 -c "import sys,json;print(len(json.load(sys.stdin)['recording']['events']),'events')"
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echo
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echo "=== 8 slowest startup steps, straight out of the recording ==="
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"$JAVA_HOME/bin/jfr" print --events 'org.springframework.core.metrics.jfr.FlightRecorderStartupEvent' \
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--json "$REC" > /tmp/startup-jfr.json 2>/dev/null
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python3 - <<'PY'
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import json
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d = json.load(open('/tmp/startup-jfr.json'))
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ev = d['recording']['events']
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print(f"{len(ev)} StartupEvent records in the recording\n")
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rows = []
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for e in ev:
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v = e['values']
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rows.append((v.get('duration', 0), v.get('name'), v.get('tags') or ''))
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rows.sort(reverse=True)
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print(f"{'duration':>14} name / tags")
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for dur, name, tags in rows[:8]:
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print(f"{dur!s:>14} {name} {tags}")
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PY
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echo
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echo "=== what JFR gives you that the buffer does not: JVM context in the same file ==="
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"$JAVA_HOME/bin/jfr" summary "$REC" | grep -E 'GCPhasePause|ClassLoad|JavaMonitorEnter|ExecutionSample|Compilation ' | head -6
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echo
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echo -n " total GC pause time during this startup: "
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"$JAVA_HOME/bin/jfr" print --events jdk.GCPhasePause --json "$REC" | python3 -c "
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import sys, json, re
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ev = json.load(sys.stdin)['recording']['events']
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tot = 0.0
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for e in ev:
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m = re.match(r'PT(?:(\d+)M)?([\d.]+)S', e['values']['duration'])
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tot += (int(m.group(1) or 0) * 60 + float(m.group(2)))
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print(f'{len(ev)} events, {tot*1000:.1f} ms')"
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true
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