jit-test

FeatureFlags.kt

package org.dummy.jmhbench

object FeatureFlags {
    val enabled: String = System.getenv("FEATURE-FLAG-ENABLED") ?: "false"
    val enabledT: Boolean = enabled.toBoolean()

    fun viaFunction(): String {
        return System.getenv("FEATURE-FLAG-ENABLED") ?: "false"
    }

    fun viaFunctionT(): Boolean {
        return (System.getenv("FEATURE-FLAG-ENABLED") ?: "false") == "true"
    }
}

MyBenchmark.kt

package org.dummy.jmhbench

import org.openjdk.jmh.annotations.*
import java.util.concurrent.TimeUnit

@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(1)
open class MyBenchmark {
    companion object {
        const val COUNT = 1024 * 1024
    }

    @Benchmark
    fun value(): Boolean {
        return FeatureFlags.enabled == "true"
    }

    @Benchmark
    fun valueT(): Boolean {
        return FeatureFlags.enabledT
    }

    @Benchmark
    fun fn(): Boolean {
        return FeatureFlags.viaFunction() == "true"
    }

    @Benchmark
    fun fnT(): Boolean {
        return FeatureFlags.viaFunctionT()
    }

    @Benchmark
    @OperationsPerInvocation(1024)
    fun throughValue(): Int {
        var a = 0
        for (i in 1 .. COUNT) {
            a += 1
            if (FeatureFlags.enabledT) {
                a += 1
            }
        }
        return a
    }

    @Benchmark
    @OperationsPerInvocation(1024)
    fun throughFunction(): Int {
        var a = 0
        for (i in 1 .. COUNT) {
            a += 1
            if (FeatureFlags.viaFunctionT()) {
                a += 1
            }
        }
        return a
    }
}

results.txt

Benchmark                    Mode  Cnt      Score     Error  Units
MyBenchmark.fn               avgt    5     35.091 ±   0.962  ns/op
MyBenchmark.fnT              avgt    5     33.893 ±   0.533  ns/op
MyBenchmark.throughFunction  avgt    5  35012.899 ± 763.721  ns/op
MyBenchmark.throughValue     avgt    5      0.002 ±   0.001  ns/op
MyBenchmark.value            avgt    5      2.242 ±   0.113  ns/op
MyBenchmark.valueT           avgt    5      2.228 ±   0.037  ns/op