asmhatre
c7eccd1db5
Custom OrderProcessed event, CPU/allocation/lock workloads, a diagnostic endpoint over the JVM's live FlightRecorder state, a JUnit test using the jdk.jfr.Recording API, and nine captured recordings (flagship, mid-flight snapshot, isolated vs concurrent threshold comparisons, and a real dump+stop duplication bug) with their docs/output/*.txt transcripts.
43 lines
2.2 KiB
Plaintext
43 lines
2.2 KiB
Plaintext
The complete, correctly-produced flagship recording for this post:
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recordings/live-demo.jfr. Produced by one JFR.start, one mid-flight JFR.dump to a
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DIFFERENT file (recordings/mid-flight-snapshot.jfr, to demonstrate inspecting a
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running recording without stopping it), and one final JFR.stop with its own
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filename= -- the pattern that avoids the duplication bug documented in
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docs/output/09-dump-duplication-bug.txt.
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$ jfr summary recordings/live-demo.jfr | head -19
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Version: 2.1
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Chunks: 2
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Start: 2026-10-01 04:29:03 (UTC)
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Duration: 6 s
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Event Type Count Size (bytes)
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=============================================================
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jdk.ModuleExport 1756 20764
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jdk.ActiveSetting 1137 30480
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jdk.BooleanFlag 992 31418
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jdk.GCPhaseParallel 570 15793
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jdk.InitialEnvironmentVariable 360 46224
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jdk.ModuleRequire 318 3498
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jdk.ObjectAllocationSample 317 5081
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jdk.LongFlag 274 9074
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jdk.NativeMethodSample 211 2532
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jdk.UnsignedLongFlag 186 6468
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jdk.ThreadPark 130 5283
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jdk.ThreadAllocationStatistics 116 1337
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The four event types this post is actually about, pulled out of the same file:
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$ jfr summary recordings/live-demo.jfr | grep -E 'ExecutionSample|ObjectAllocationSample|JavaMonitorEnter|OrderProcessed'
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jdk.ObjectAllocationSample 317 5081
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jdk.ExecutionSample 98 1176
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com.ankurm.jfr.OrderProcessed 23 809
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jdk.JavaMonitorEnter 15 414
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317 allocation samples, 98 CPU samples (63% of them in the one hot method --
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docs/output/03-hot-method-samples.txt), 23 kept custom business events out of 60
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calls (docs/output/06-custom-event-live-demo.txt), and 15 monitor-enter events
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from one 16-worker contention burst (docs/output/05-lock-contention-live-demo.txt)
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-- all from a recording six seconds long, on an application that otherwise just
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sits idle.
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