RFR: 8331341: secondary_super_cache does not scale well: C1 and interpreter [v5]

[Andrew Haley]

On Tue, 23 Jul 2024 19:14:57 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> > Also also, Klass::is_subtype_of() is used for C1 runtime.
> 
> Can you elaborate, please?

Sorry, that was rather vague. In C1-compiled code, the Java method `Class::isInstance(Object)`calls `Klass::is_subtype_of()`. 

In general, I find it difficult to decide how much work, if any, should be done to improve C1 performance. Clearly, if C1 exists only to help with startup time in a tiered compilation system, the answer is "not much".

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PR Review Comment: https://git.openjdk.org/jdk/pull/19989#discussion_r1689414385