RFR: 8352738: Implement JEP 520: JFR Method Timing and Tracing

[Erik Gahlin]

On Thu, 22 May 2025 12:24:23 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Could I have a review of this enhancement that will add tracing capabilities to JFR? There are opportunities for performance improvements in the implementation, but I would rather add them later and separately.
>> 
>> Testing: tier 1-3, test/jdk/jdk/jfr
>> 
>> Thanks
>> Erik
>
> src/jdk.jfr/share/classes/jdk/jfr/internal/tracing/PlatformTracer.java line 273:
> 
>> 271:             JVM.exclude(current);
>> 272:             long classId = Type.getKnownType(String.class).getId();
>> 273:             long methodId = classId << 16 + 983059;
> 
> What's `983059`?

It's just a method ID I happened to get when I instrumented some random method in java.lang.String. I can add a comment explaining it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25306#discussion_r2102559617