Performance degradation in Oracle GraalVM JDK 25ea

[plokhotnyuk]

Describe the issue
About 9x performance degradation detected for Oracle GraalVM for JDK 25 comparing to GraalVM Community.

Steps to reproduce the issue

1. git clone --depth 1 https://github.com/plokhotnyuk/jsoniter-scala
2. sbt ++3.6.3 jsoniter-scala-benchmarkJVM/assembly
3. /usr/lib/jvm/graalvm-jdk-25/bin/java -jar jsoniter-scala-benchmark/jvm/target/scala-3.6.3/benchmarks.jar -p size=128 BigDecimalReading.*jsoniterScala

Describe GraalVM and your environment:

• GraalVM version is the latest snapshot build
• JDK major version: 25ea
• OS: Ubuntu 24.04
• Architecture: AMD64

More details
Below are results of benchmarks from Intel® Core™ i7-11800H (but the similar performance drop is reproducible on Intel® Core™ Ultra 9 285K):

GraalVM Community

Benchmark                        (size)   Mode  Cnt        Score        Error  Units
BigDecimalReading.jsoniterScala     128  thrpt    5  9384303.990 ± 421621.535  ops/s

Oracle GraalVM

Benchmark                        (size)   Mode  Cnt        Score        Error  Units
BigDecimalReading.jsoniterScala     128  thrpt    5  1021826.995 ± 251967.185  ops/s

Adding -XX:TieredStopAtLevel=1 helps to reduce performance drop a bit for Oracle GraalVM:

Benchmark                        (size)   Mode  Cnt        Score       Error  Units
BigDecimalReading.jsoniterScala     128  thrpt    5  2610858.435 ± 40855.634  ops/s

[davleopo]

Thanks @plokhotnyuk - we will have a look.

[davleopo]

Tracked internally as GR-62248.