RFR: 8370203 - Add jcmd AOT.end_recording diagnostic command [v5]

[Leonid Mesnik]

On Thu, 20 Nov 2025 16:22:29 GMT, Mat Carter <macarte at openjdk.org> wrote:

>> Add jcmd AOT.end_recording diagnostic command.  When this command is issued, a targeted JVM that is currently recording AOT information will stop recording.  Existing functionality is preserved: when stopped the JVM will create the required artifacts based on the execution mode.  Conveniently as the application running on the JVM has not stopped (as was previously the only way to stop recording), the application will resume execution after the artifacts have been generated.
>> 
>> The command will report back to the user one of the following messages depending on the state of the JVM:
>> 
>> - AOT.end_recording is unsupported when VM flags -XX:AOTMode=record or -XX:AOTCacheOutput=<file> are missing
>> - Recording has already ended.
>> - Error: Failed to end recording.
>> - Recording ended successfully.
>> 
>> It follows that issues the command to a JVM that is recording, twice in succession, should (baring internal errors) would produce the following two responses:
>> 
>> - Recording ended successfully.
>> - Recording has already ended.
>> 
>> Passes tier1 on linux (x64) and windows (x64)
>
> Mat Carter has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Merge branch 'JDK-8370203' of https://github.com/macarte/jdk into JDK-8370203
>  - Corrected placement of assert and logic test

Changes requested by lmesnik (Reviewer).

src/hotspot/share/cds/aotMetaspace.cpp line 1062:

> 1060: bool AOTMetaspace::preimage_static_archive_dumped() {
> 1061:   assert(CDSConfig::is_dumping_preimage_static_archive(), "Required");
> 1062:   return _preimage_static_archive_dumped == 1;

Should it be  AtomicAccess::load(&_preimage_static_archive_dumped) here?

test/hotspot/jtreg/runtime/cds/appcds/aotCache/DiagnosticCommandMBeanTest.java line 98:

> 96:                     out.shouldContain("Failed to stop recording");
> 97:                 }
> 98:                 out.shouldNotContain("IOException occurred!");

The 'IOException occurred!' is never printed. While there are a lot of other exception print and not checked.

Also makes sense to check exit status.

test/hotspot/jtreg/runtime/cds/appcds/aotCache/JcmdAOTEndRecordingTest.java line 31:

> 29:  * @summary Sanity test for Jcmd AOT.end_recording command
> 30:  * @library /test/lib
> 31:  * @build JcmdAOTEndRecordingTest

No need to build test explicitly, jtreg does it by itself.

test/hotspot/jtreg/runtime/cds/appcds/aotCache/JcmdAOTEndRecordingTest.java line 57:

> 55:             try {
> 56:                 OutputAnalyzer output = ProcessTools.executeProcess(jcmd.getCommand());
> 57:                 output.shouldContain("AOT.end_recording is unsupported");

A little bit confused.  The check doesn't match test description.

-------------

PR Review: https://git.openjdk.org/jdk/pull/27965#pullrequestreview-3490649441
PR Review Comment: https://git.openjdk.org/jdk/pull/27965#discussion_r2548182449
PR Review Comment: https://git.openjdk.org/jdk/pull/27965#discussion_r2548168094
PR Review Comment: https://git.openjdk.org/jdk/pull/27965#discussion_r2548140140
PR Review Comment: https://git.openjdk.org/jdk/pull/27965#discussion_r2548148536