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77 строки
2.7 KiB
Plaintext
77 строки
2.7 KiB
Plaintext
https://docs.oracle.com/en/java/javase/22/jfapi/why-use-jfr-api.html
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https://inside.java/tag/jfr
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2024
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Java - Joakim Nordstrom - Programmer's Guide to JDK Flight Recorder 31:00 of 36:55
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https://www.youtube.com/watch?v=AgFOJEkBVjg
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! default conf is at lib/jfr/default.jfc, profile.jfc
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! java -XX:StartFlightRecording # less than 1% overhead
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! java -XX:StartFlightRecording:maxage=10m,maxsize=750M
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! java -XX:StartFlightRecording:dumponexit=true,filename=/var/log/rec_%p_%t.jfr
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! ... at runtime ...
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! jcmd <pid> JFR.start
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! jcmd <pid> JFR.dump
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! jcmd <pid> JFR.stop
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! jcmd <pid> JFR.check
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! 20496:
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! Recording 1: name=1 maxsize=250,0Mb (running)
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! jfr summary <file>.jfr
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! jfr view --verbose <file>.jfr
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! jfr help view # 70 predefined views
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@Name("inside.dumpster.ServiceCall")
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@Label("Service.Call")
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@Category({"Business Application", "Services"})
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public class ServiceCallEvent extends jdk.jfr.Event {
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@Label("Service Destination")
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public String destination;
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@Name("serviceClass")
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@Label("Service Implementation Class")
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public Class serviceImplClass;
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}
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Hello event = new Hello();
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event.begin();
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...
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event.message = "Hello Event!";
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...
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event.commit();
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! monitoring
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Configuration conf = Configuration.getConfiguration("default");
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try (var stream = new RecordingStream(conf)) {
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stream.enable("jdk.CPULoad").withPeriod(Duration.ofSeconds(1));
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stream.onEvent("jdk.CPULoad", event -> {
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float cpuLoad = event.getFloat("jvmUser");
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if (cpuLoad > 0.8) {
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stream.dupm(dupmPath);
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}
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});
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stream.start();
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}
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! instead of using a RecordingStream we can use RemoteRecordingStream
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! ... stream.startAsync();
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! stream.stop(); // new in JDK 20
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https://github.com/moditect/jfrunit
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import org.moditect.jfrunit.events.JfrEventTypes;
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https://github.com/moditect/jfrunit-examples
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https://github.com/moditect/jfr-analytics
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some interesting field annotations
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@DataAmount
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@MemoryAddress
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@Frequency
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@Percentage
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2023
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Java - Continuous Monitoring with JDK Flight Recorder 0:00 of 45:55
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https://www.youtube.com/watch?v=Gx_JGVborJ0
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2022
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Java - Programmer's Guide to JDK Flight Recorder of 24:08
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https://www.youtube.com/watch?v=K1ApBZGiT-Y
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2020
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Vidstedt - Continuous Monitoring with JDK Flight Recorder
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https://www.youtube.com/watch?v=plYESjZ12hM
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Gronlund - JDK11 - Introduction to JDK Flight Recorder
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https://www.youtube.com/watch?v=7z_R2Aq-Fl8
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https://www.infoq.com/presentations/monitoring-jdk-jfr/
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