asmhatreandClaude Sonnet 5
0819993c51
Reproduces the pinning JEP 491 did not fix (native JNI frames) with a real native library, alongside the monitor case it did fix. Covers the jdk.VirtualThreadPinned JFR event, reading pinned vs unmounted virtual threads from a jcmd Thread.dump_to_file, the measured throughput cost on a capped carrier pool, and a bounded-executor pattern to contain the blast radius. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01FhzLY5p6okFva3qsnsRyvM
30 lines
1.1 KiB
Plaintext
30 lines
1.1 KiB
Plaintext
$ java -XX:StartFlightRecording=...,jdk.VirtualThreadPinned#enabled=true,threshold=0ms NativePinningDemo
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java.version=25.0.4.1
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jdk.tracePinnedThreads=null
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sleepMillis=200
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done
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$ jfr print --events jdk.VirtualThreadPinned --stack-depth 10 target/native-pin.jfr
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jdk.VirtualThreadPinned {
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startTime = 12:02:49.269 (2026-09-30)
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duration = 200 ms
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blockingOperation = "LockSupport.park"
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pinnedReason = "Native or VM frame on stack"
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carrierThread = "ForkJoinPool-1-worker-1" (javaThreadId = 28)
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eventThread = "" (javaThreadId = 27, virtual)
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stackTrace = [
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java.lang.VirtualThread.parkOnCarrierThread(boolean, long) line: 833
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java.lang.VirtualThread.parkNanos(long) line: 801
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java.lang.VirtualThread.sleepNanos(long) line: 983
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java.lang.Thread.sleepNanos(long) line: 507
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java.lang.Thread.sleep(long) line: 540
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com.ankurm.vtpinning.NativePinningDemo.sleepCallback() line: 30
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com.ankurm.vtpinning.NativePinningDemo.blockingNativeCall()
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java.lang.VirtualThread.run(Runnable) line: 460
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jdk.internal.vm.Continuation.enterSpecial(Continuation, boolean, boolean)
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]
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}
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