RFR: 8348556: Inlining fails earlier for MemorySegment::reinterpret [v6]

[Maurizio Cimadamore]

On Tue, 8 Apr 2025 12:13:25 GMT, Per Minborg <pminborg at openjdk.org> wrote:

> Baseline:
> 
> ```
> Benchmark                            (offsetCount)  (segmentSize)   Mode  Cnt        Score       Error  Units
> FFMVarHandleInlineTest.t0_reference           2048           1024  thrpt   25  1552613.262 ? 14295.035  ops/s
> FFMVarHandleInlineTest.t1_level8              2048           1024  thrpt   25  1558465.228 ?  8458.874  ops/s
> FFMVarHandleInlineTest.t2_level9              2048           1024  thrpt   25  1542009.100 ? 10240.173  ops/s
> FFMVarHandleInlineTest.t3_level10             2048           1024  thrpt   25  1553407.503 ? 10834.133  ops/s
> FFMVarHandleInlineTest.t4_level11             2048           1024  thrpt   25    87666.558 ?   765.848  ops/s. <-- We hit the inline limit here
> ```
> 
> Patch without `Object` changes:
> 
> ```
> Benchmark                         (offsetCount)  (segmentSize)   Mode  Cnt       Score      Error  Units
> FFMVarHandleInlineTest.t_level11           2048           1024  thrpt    6  149221.636 ± 1928.957  ops/s
> FFMVarHandleInlineTest.t_level12           2048           1024  thrpt    6   74478.268 ± 1093.429  ops/s
> FFMVarHandleInlineTest.t_level13           2048           1024  thrpt    6   74490.972 ±  623.857  ops/s
> FFMVarHandleInlineTest.t_level14           2048           1024  thrpt    6   69637.549 ± 2497.253  ops/s
> FFMVarHandleInlineTest.t_level15           2048           1024  thrpt    6    3495.106 ±   87.465  ops/s
> ```
> 
> Patch with `Object` changes:
> 
> ```
> Benchmark                         (offsetCount)  (segmentSize)   Mode  Cnt       Score      Error  Units
> FFMVarHandleInlineTest.t_level11           2048           1024  thrpt    6  1545991.924 ± 21206.450  ops/s
> FFMVarHandleInlineTest.t_level12           2048           1024  thrpt    6  1542234.193 ± 18002.511  ops/s
> FFMVarHandleInlineTest.t_level13           2048           1024  thrpt    6  1542601.822 ± 15041.864  ops/s
> FFMVarHandleInlineTest.t_level14           2048           1024  thrpt    6   179053.325 ±  2496.002  ops/s
> FFMVarHandleInlineTest.t_level15           2048           1024  thrpt    6     3433.861 ±   165.847  ops/s
> ```

am I reading this the right way around? Baseline is faster than the patched version?

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PR Comment: https://git.openjdk.org/jdk/pull/23460#issuecomment-2794329053