RFR: 8335358: [premain] Explore alternative ways to trigger the end of training run [v5]

[Ioi Lam]

On Mon, 16 Sep 2024 22:18:30 GMT, Mat Carter <macarte at openjdk.org> wrote:

>> AOT training can be ended using either
>> 
>> - -XX: AOTEndTrainingOnMethodEntry =Hello.someMethod [same syntax as CompileOnly]
>> - -XX: AOTEndTrainingOnMethodEntry =Hello.someMethod,Hello.someOtherMethod,count=42
>> - jcmd <pid> AOT.end_training
>> 
>> supports arm64 and x64
>> 
>> note: the AOTEndTrainingOnMethodEntry is ignored when CDSPreImage is specified; this is needed as the phase2 forked java process is passed all phase1 flags along with the -XX:CDSPreImage, but we don't want to run the trigger code in this phase (there may be a better way to handle this state or simply remove the flag from the forked process)
>> 
>> JBS Issue: https://bugs.openjdk.org/browse/JDK-8335358
>
> Mat Carter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   removed extra space left over from reverted change

I would suggest adding some sanity test cases. You can make a copy of test/hotspot/jtreg/runtime/cds/appcds/leyden/LeydenHello.java and rename the classes accordingly. Then, add the following to the `Tester` inner class:


        @Override
        public String[] vmArgs(RunMode runMode) {
            return new String[] {
                 "-XX: AOTEndTrainingOnMethodEntry=??????",
            };
        }


For jcmd, you can make a copy of test/hotspot/jtreg/runtime/cds/appcds/jcmd/JCmdTestStaticDump.java, strip most of it and leave only one copy of this:


        app  = createLingeredApp("-XX:CacheDataStore=foo.cds", "-cp", allJars);
        pid = app.getPid();
        test("foo.cds", pid, .....);
        app.stopApp();


You also need to modify JCmdTestDumpBase.java so it can dispatch the "AOT.end_training" command instead.

> note: the AOTEndTrainingOnMethodEntry is ignored when CDSPreImage is specified

I think this is OK. Filtering out the option from the command-line is non trivial; ignoring it is much simpler.

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

PR Comment: https://git.openjdk.org/leyden/pull/21#issuecomment-2354464924