RFR: 8344068: Windows x86-64: Out of CodeBuffer space when generating final stubs

[Andrew Haley]

On Mon, 9 Dec 2024 09:05:44 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Okay, thank you for details.
>
> FTR,
> Following are the final stub section sizes with and without -XX:+UseZGC on linux and windows
> 
> 
> Linux
>  - With ZGC
>     [0.928s][info][stubs] StubRoutines (final stubs)         [0x00007fb1afc320c0, 0x00007fb1afc3e550] used: 41659, free: 8661
>  - Without ZGC
>  -  [0.019s][info][stubs] StubRoutines (final stubs)         [0x00007f5e6fc2cc40, 0x00007f5e6fc390d0] used: 27419, free: 22901
> 
> 
> 
> Windows:
>    - With ZGC 
>    -  [0.043s][info][stubs] StubRoutines (final stubs)         [0x00000291ea5684c0, 0x00000291ea575120] used: 45870, free: 6450
>    - Without ZGC
>    - [0.039s][info][stubs] StubRoutines (final stubs)         [0x000002003a1e31c0, 0x000002003a1efe20] used: 30030, free: 22290
> 
> 
> Hi @theRealAph , it will really help if you could kindly share the details to justify this increase.

We're seeing only 500 bytes remaining on AVX-512 machines, and I have not checked it all (there's a *lot* of code) but the samples I looked at were all much bigger because of AVX-512 stubs.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22516#discussion_r1875787230