RFR: JDK-8298255: JFR provide information about dynamization of number of compiler threads [v2]

[Erik Gahlin]

On Thu, 8 Dec 2022 13:12:51 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> The JVM supports both dynamic GC threads, and dynamic Compiler threads.
>> While the GCConfiguration JFR event (see https://sap.github.io/SapMachine/jfrevents/#gcconfiguration ) seems to have at least some info about dynamization of GC threads ( field usesDynamicGCThreads), the JIT CompilerConfiguration event seems to miss this info (about JIT compiler threads dynamization), this should be added; currently the impression is given that the number is static but this is often not the case.
>> As an extension, the dynamization process of adding / removing threads could be added as well to the JFR events but I am not sure if this is desired so I just started with a very simple patch.
>
> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
> 
>   event field names must not be longer than 32 chars

test/jdk/jdk/jfr/event/compiler/TestCompilerConfig.java line 55:

> 53:             Events.assertField(event, "threadCount").atLeast(0);
> 54:             Events.assertField(event, "tieredCompilation");
> 55:             Events.assertField(event, "usesDynamicNrOfCompilerThreads");

"NrOf" looks strange. Can we come up with a better name?

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PR: https://git.openjdk.org/jdk/pull/11563