asmhatre
f506b01389
Companion module for the rewritten post 'Virtual Threads on Spring Boot 4.1: The Benchmarks, Re-Run, and the Pinning Advice That Expired', retitled and re-benchmarked on Boot 4.1.1 / JDK 25.0.4.1 (the original post was written against Boot 3.4 / JDK 21). Covers: I/O-bound and CPU-bound throughput (platform vs virtual threads, including a JIT-warmup benchmarking bug this build caught and fixed), JEP 491 proof that synchronized no longer pins a virtual thread's carrier across a blocking call as of JDK 24 (obsoleting the old avoid-synchronized advice), proof that -Djdk.tracePinnedThreads=full is inert on JDK 25, and JEP 506's finalized ScopedValue API (JDK 25 GA, no --enable-preview, and a different shape than the old preview API). Kept as its own module rather than a new top-level repository, alongside the existing async/ module, which already has a stronger dual-JDK JEP 491 proof that this module's docs cross-link to instead of duplicating.
28 lines
1.4 KiB
Java
28 lines
1.4 KiB
Java
package com.ankurm.vthreads;
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/**
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* Standalone (no Spring context) check that -Djdk.tracePinnedThreads=full is inert on this
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* JDK. Pre-JDK-24, this flag made the JVM print a stack trace to stdout every time a virtual
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* thread pinned its carrier. JEP 491 removed the property along with most of the pinning it
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* used to report on: "setting it on the command line will have no effect." Run via
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* scripts/check-trace-pinned-threads-removed.sh, which invokes this twice (with and without
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* the flag) and diffs the output. See docs/03-pinning-diagnosis.md.
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*/
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public class PinningTraceCheckMain {
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public static void main(String[] args) throws Exception {
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System.out.println("java.version=" + System.getProperty("java.version"));
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System.out.println("jdk.tracePinnedThreads=" + System.getProperty("jdk.tracePinnedThreads"));
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System.out.println("Running a virtual thread that holds a monitor across Thread.sleep(200)...");
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Thread vt = Thread.ofVirtual().start(() -> {
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try {
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PinningDemoService.doWorkHoldingMonitor(200);
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} catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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});
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vt.join();
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System.out.println("Done. If jdk.tracePinnedThreads still worked on this JDK, a pinned-thread " +
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"stack trace would have printed above while the virtual thread was inside doWorkHoldingMonitor.");
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}
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}
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