RFR: 8356025: Provide a PrintVMInfoAtExit diagnostic switch

[Joel Sikström]

On Thu, 1 May 2025 04:54:37 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Provides a `PrintVMInfoAtExit` diagnostic switch that, if active, causes the JVM to print out the equivalent of `jcmd VM.info` before exiting.
> 
> The `VM.info` output contains a large range of valuable information about the JVM and the process.
> 
> The switch can be surprisingly useful, e.g. when analysing short-lived processes that are too quick to be analysed with jcmd, or analysing JVM child processes in a process tree, and so on. Going forward, it can also remove the need for some of the more specific PrintxxxAtExit flags.
> 
> It can also make writing tests easier (want to make sure switch XX enables condition YY, and YY is printed as part of VM.info? Just start the VM with PrintVMInfoAtExit and parse the output )

I really like this. Will be useful when testing and developing printing code.

src/hotspot/share/runtime/globals.hpp line 706:

> 704:                                                                             \
> 705:   product(bool, PrintVMInfoAtExit, false, DIAGNOSTIC,                       \
> 706:           "Executes the the VM.info diagnostic command at exit")            \

Suggestion:

          "Executes the VM.info diagnostic command at exit")            \

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Marked as reviewed by jsikstro (Committer).

PR Review: https://git.openjdk.org/jdk/pull/24980#pullrequestreview-2820910157
PR Review Comment: https://git.openjdk.org/jdk/pull/24980#discussion_r2077124746