RFR: JDK-8180450: secondary_super_cache does not scale well [v4]

[Chris Plummer]

On Tue, 19 Mar 2024 10:01:49 GMT, Andrew Haley <aph at openjdk.org> wrote:

>>> Hi Andrew, we'd most likely want to port this to Graal. Just for my understanding, the current implementation of [secondary super cache lookup in Graal](https://github.com/oracle/graal/blob/0a471fc329ea2c8c18c05f9d83347dc1199c3ad9/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/replacements/InstanceOfSnippets.java#L169) will continue to work until we get around to doing the port right?
>> 
>> Absolutely, yes. This is purely an add-on for now.
>
>> > Hi Andrew, we'd most likely want to port this to Graal. Just for my understanding, the current implementation of [secondary super cache lookup in Graal](https://github.com/oracle/graal/blob/0a471fc329ea2c8c18c05f9d83347dc1199c3ad9/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/replacements/InstanceOfSnippets.java#L169) will continue to work until we get around to doing the port right?
>> 
>> Absolutely, yes. This is purely an add-on for now.
> 
> To clarify: I can't see anything in there that is sensitive to the order in which the secondary supers appear, and unless code looks at the hash bitmap, the only change it sees is the order of the secondaries.

@theRealAph I applied your patch and ran SA tests. I did not see the failures you mentioned to me. Is there anything else special I need to do?

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PR Comment: https://git.openjdk.org/jdk/pull/18309#issuecomment-2013022762