Benchmark of Mono::singleOptional vs map + defaultIfEmpty

MonoOptionalBenchmark.java

@BenchmarkMode({Mode.AverageTime})
@Warmup(iterations = 5, time = 5, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 5, timeUnit = TimeUnit.SECONDS)
@Fork(value = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
public class MonoOptionalBenchmark {

	private static final Throwable EXCEPTION = new RuntimeException() {
		@Override
		public synchronized Throwable fillInStackTrace() {
			return this;
		}
	};

	@Benchmark
	public void singleOptionalBaseline(Blackhole blackhole) {
		blackhole.consume(
				Mono.just(1)
				    .map(Optional::ofNullable)
				    .defaultIfEmpty(Optional.empty())
				    .block()
		);
	}

	@Benchmark
	public void singleOptionalEmptyBaseline(Blackhole blackhole) {
		blackhole.consume(
				Mono.empty()
				    .map(Optional::ofNullable)
				    .defaultIfEmpty(Optional.empty())
				    .block()
		);
	}

	@Benchmark
	public void singleOptionalErrorBaseline(Blackhole blackhole) {
		blackhole.consume(
				Mono.error(EXCEPTION)
				    .map(Optional::ofNullable)
				    .defaultIfEmpty(Optional.empty())
				    .onErrorComplete()
				    .block()
		);
	}

	@Benchmark
	public void singleOptional(Blackhole blackhole) {
		blackhole.consume(
				Mono.just(1)
				    .singleOptional()
				    .block()
		);
	}

	@Benchmark
	public void singleOptionalEmpty(Blackhole blackhole) {
		blackhole.consume(
				Mono.empty()
				    .singleOptional()
				    .block()
		);
	}

	@Benchmark
	public void singleOptionalError(Blackhole blackhole) {
		blackhole.consume(
				Mono.error(EXCEPTION)
				    .singleOptional()
				    .onErrorComplete()
				    .block()
		);
	}
}

Benchmark                                          Mode  Cnt   Score   Error  Units
MonoOptionalBenchmark.singleOptional               avgt    5   4.284 ± 0.096  ns/op
MonoOptionalBenchmark.singleOptionalBaseline       avgt    5  38.576 ± 0.091  ns/op
MonoOptionalBenchmark.singleOptionalEmpty          avgt    5   0.591 ± 0.006  ns/op
MonoOptionalBenchmark.singleOptionalEmptyBaseline  avgt    5  32.916 ± 0.343  ns/op
MonoOptionalBenchmark.singleOptionalError          avgt    5  23.348 ± 0.165  ns/op
MonoOptionalBenchmark.singleOptionalErrorBaseline  avgt    5  59.782 ± 0.774  ns/op