On Thu, 30 May 2024 16:39:03 GMT, Alan Bateman <al...@openjdk.org> wrote:
>> Print the stack traces of mounted virtual threads when calling `jcmd <pid> >> Thread.print`. > > Thanks for take this one. Here's the result with the changes in 1a75277e. > > "ForkJoinPool-1-worker-1" #25 [33795] daemon prio=5 os_prio=31 cpu=46574.42ms > elapsed=47.15s tid=0x00007f81670d1a00 [0x000070000e9a4000] > Carrying virtual thread #24 > at jdk.internal.vm.Continuation.run(java.base/Continuation.java:262) > at > java.lang.VirtualThread.runContinuation(java.base/VirtualThread.java:283) > at > java.lang.VirtualThread$$Lambda/0x00000001220b2868.run(java.base/Unknown > Source) > at > java.util.concurrent.ForkJoinTask$RunnableExecuteAction.compute(java.base/ForkJoinTask.java:1726) > at > java.util.concurrent.ForkJoinTask$RunnableExecuteAction.compute(java.base/ForkJoinTask.java:1717) > at > java.util.concurrent.ForkJoinTask$InterruptibleTask.exec(java.base/ForkJoinTask.java:1641) > at > java.util.concurrent.ForkJoinTask.doExec(java.base/ForkJoinTask.java:507) > at > java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(java.base/ForkJoinPool.java:1455) > at > java.util.concurrent.ForkJoinPool.runWorker(java.base/ForkJoinPool.java:2031) > at > java.util.concurrent.ForkJoinWorkerThread.run(java.base/ForkJoinWorkerThread.java:189) > Carrying virtual thread #24 > at Main.lambda$main$0(Main.java:7) > at java.lang.VirtualThread.run(java.base/VirtualThread.java:381) > > > Note that the line "Carrying virtual thread #24" is printed twice. Also it's > not immediately clear that there are two stack traces. > > You'll likely get different opinions on how mounted virtual threads should be > presented. A few things to try > - indent the stack trace of the mounted virtual thread > - list the mounted virtual threads at the end Thanks for your comments @AlanBateman and @dholmes-ora ! - The format proposed by @dholmes-ora definitely makes sense and I'll of course drop the duplicated "Carrying" statement. - Regarding using `JavaThread::print_vthread_stack_on`, I agree that it'd be good to use it instead of creating a new way of printing stack traces. However `print_vthread_stack_on` does not have the `const` modifier so it cannot be called directly from `Thread.print_on`. Making `print_vthread_stack_on` more strict, seems to be fairly complicated and I don't know if I'd be OK with relaxing the `const` constraint in `Thread.print_on` for the purpose of reusing `print_vthread_stack_on` ------------- PR Comment: https://git.openjdk.org/jdk/pull/19482#issuecomment-2141946811
