RFR: 8216303: JFR: Simplify generated files

[Erik Joelsson]

Hello Erik,

I noticed that you added an import for java.util.HashSet, but it doesn't 
seem to be used. You also replaced the only use of HashMap with 
LinkedHashMap, which we like as it gives a predictable iteration order, 
but forgot to remove the import.

Do you know if the generated files are stable over several builds?

/Erik

On 2020-05-28 10:37, Erik Gahlin wrote:
> Hi,
>
> Could I have a review of a fix that removes legacy in the generated JFR event files, in particular hard coded numbers for type / event IDs. Event IDs are now numbered from zero, which has the benefit that most of them can be represented as a single byte instead of two. This will reduce the size of recordings with a few percent.
>
> I’m looping in build-dev, since I am modifying make/src/classes/build/tools/jfr/GenerateJfrFiles.java, but there are no changes to how things are built. The generated JFR files are just slightly different.
>
> Old and new files:
> http://cr.openjdk.java.net/~egahlin/8216303_generated/
>
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8216303
>
> Webrev:
> http://cr.openjdk.java.net/~egahlin/8216303/
>
> Testing:
> - Building with and without jfr the feature enabled
> - Tier 1/2 (Mac, Linux and Windows)
> - JFR tests in test/jdk/jdk/jfr
>
> Thanks
> Erik
>
>