RFR: 8331117: [PPC64] secondary_super_cache does not scale well [v2]

[Andrew Haley]

On Sat, 15 Jun 2024 09:03:57 GMT, Andrew Haley <aph at openjdk.org> wrote:

>>> That doesn't look like a platform specific thing. I'm getting the same result on x86_64. @theRealAph: Is that a known limitation or is it worth a new JBS issue?
>> 
>> I've never seen this. It must be a regression. I'll have a look.
>
>> That doesn't look like a platform specific thing. I'm getting the same result on x86_64. @theRealAph: Is that a known limitation or is it worth a new JBS issue?
> 
> Ah, I see. The test is doing some IR node counts for Klass loads, and `-UseSecondarySupersCache` deletes one of those loads. So it's not actually a behavioural change. I'm not sure what to do about this.

> > > That doesn't look like a platform specific thing. I'm getting the same result on x86_64. @theRealAph: Is that a known limitation or is it worth a new JBS issue?
> > 
> > 
> > Ah, I see. The test is doing some IR node counts for Klass loads, and `-UseSecondarySupersCache` deletes one of those loads. So it's not actually a behavioural change. I'm not sure what to do about this.
> 
> Maybe file an issue and ask the IR test folks to take a look? I don't think this PR is a good place to discuss it.

The tests are not all expected to work with arbitrary combinations of -XX arguments. In many cases, they will surely fail. I'll be working on a followup patch that will remove all uses of `secondary_super_cache`, and at that point the test will need to be fixed.

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PR Comment: https://git.openjdk.org/jdk/pull/19368#issuecomment-2173061620