`EnableX86ECoreOpts` has been introduced in JDK-8319429, however model numbers which should be enabled are hard-coded, so the flag would not be enabled by default on some models like Arrow Lake.

I ran a benchmark [1] to check for effectiveness of `-XX:+EnableX86ECoreOpts` with JDK 25.0.1 on Windows 11 25H2, I saw performance improvement a bit on Intel Core 5 Ultra 225U as following:

Disabled (default)
```
Benchmark Mode Cnt Score Error Units
RandMinVal.getMax thrpt 3 9707774.405 ± 27082629.015 ops/s
RandMinVal.getMin thrpt 3 7510319.839 ± 10923547.382 ops/s
```

Enabled
```
Benchmark Mode Cnt Score Error Units
RandMinVal.getMax thrpt 3 10127809.127 ± 45404142.338 ops/s
RandMinVal.getMin thrpt 3 8467677.056 ± 1211998.200 ops/s
```

So I think it is better to enable this flag by default on all of hybrid CPUs.


[1] https://github.com/YaSuenag/garakuta/tree/master/randminmax