Integrated: 8329126: No native wrappers generated anymore with -XX:-TieredCompilation after JDK-8251462

[Volker Simonis]

On Tue, 26 Mar 2024 19:14:23 GMT, Volker Simonis <simonis at openjdk.org> wrote:

> Since [JDK-8251462: Simplify compilation policy](https://bugs.openjdk.org/browse/JDK-8251462), introduced in JDK 17, no native wrappers are generated any more if running with `-XX:-TieredCompilation` (i.e. native methods are not compiled any more).
> 
> The attached JMH benchmark demonstrate that native method calls became twice as expensive with JDK 17:
> 
>   public static native void emptyStaticNativeMethod();
> 
>   @Benchmark
>   public static void baseline() {
>   }
> 
>   @Benchmark
>   public static void staticMethodCallingStatic() {
>     emptyStaticMethod();
>   }
> 
>   @Benchmark
>   public static void staticMethodCallingStaticNative() {
>     emptyStaticNativeMethod();
>   }
> 
>   @Benchmark
>   @Fork(jvmArgsAppend = "-XX:-TieredCompilation")
>   public static void staticMethodCallingStaticNativeNoTiered() {
>     emptyStaticNativeMethod();
>   }
> 
>   @Benchmark
>   @Fork(jvmArgsAppend = "-XX:+PreferInterpreterNativeStubs")
>   public static void staticMethodCallingStaticNativeIntStub() {
>     emptyStaticNativeMethod();
>   }
> 
> 
> JDK 11
> ======
> 
> Benchmark                                           Mode  Cnt   Score   Error  Units
> NativeCall.baseline                                 avgt    5   0.390 ± 0.016  ns/op
> NativeCall.staticMethodCallingStatic                avgt    5   1.693 ± 0.053  ns/op
> NativeCall.staticMethodCallingStaticNative          avgt    5  10.287 ± 0.754  ns/op
> NativeCall.staticMethodCallingStaticNativeNoTiered  avgt    5   9.966 ± 0.248  ns/op
> NativeCall.staticMethodCallingStaticNativeIntStub   avgt    5  20.384 ± 0.444  ns/op
> 
> 
> JDK 17 & 21
> ===========
> 
> Benchmark                                           Mode  Cnt   Score   Error  Units
> NativeCall.baseline                                 avgt    5   0.390 ± 0.017  ns/op
> NativeCall.staticMethodCallingStatic                avgt    5   1.852 ± 0.272  ns/op
> NativeCall.staticMethodCallingStaticNative          avgt    5  10.648 ± 0.661  ns/op
> NativeCall.staticMethodCallingStaticNativeNoTiered  avgt    5  20.657 ± 1.084  ns/op
> NativeCall.staticMethodCallingStaticNativeIntStub   avgt    5  22.429 ± 0.991  ns/op
> 
> 
> The issue can bee seen if we run with `-XX:+PrintCompilation -XX:+PrintInlining`. With JDK 11 we get the following output for `-XX:+TieredCompilation`:
> 
>     172  111    b  3       io.simonis.NativeCall::staticMethodCallingStaticNative (4 bytes)
>                               @ 0   io.simonis.NativeCall::emptyStaticNativeMethod (0 bytes)   native method
>     172  112     n 0       io.simonis.NativeCall::emptyStaticNativeMethod (native...

This pull request has now been integrated.

Changeset: f2e5808b
Author:    Volker Simonis <simonis at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/f2e5808b46a3da6920dd56688c877ee0e2795de6
Stats:     115 lines in 3 files changed: 114 ins; 0 del; 1 mod

8329126: No native wrappers generated anymore with -XX:-TieredCompilation after JDK-8251462

Reviewed-by: kvn, iveresov, vlivanov

-------------

PR: https://git.openjdk.org/jdk/pull/18496