NOTE:   The latest version of the library changes how the plugin and runtime library dependencies are declared:

• The library runtime is published to Maven Central and no longer published to Bintray.
• The Gradle plugin is published to Gradle Plugin Portal
• The Gradle plugin id has changed to org.jetbrains.kotlinx.benchmark
• The library runtime artifact id has changed to kotlinx-benchmark-runtime

kotlinx.benchmark is a toolkit for running benchmarks for multiplatform code written in Kotlin and running on the next supported targets: JVM, JavaScript.

Technically it can be run on Native target, but current implementation doesn't allow to get right measurements in many cases for native benchmarks, so it isn't recommended to use this library for native benchmarks yet. See issue for more information.

If you're familiar with JMH, it is very similar and uses it under the hoods to run benchmarks on JVM.

Requirements

Gradle 6.8 or newer

Kotlin 1.4.30 or newer

Gradle plugin

Use plugin in build.gradle:

plugins {
    id 'org.jetbrains.kotlinx.benchmark' version '0.3.0'
}

For Kotlin/JS specify building nodejs flavour:

kotlin {
    js {
        nodejs()
        …
    }   
}

For Kotlin/JVM code, add allopen plugin to make JMH happy. Alternatively, make all benchmark classes and methods open.

For example, if you annotated each of your benchmark classes with @State(Scope.Benchmark):

@State(Scope.Benchmark)
class Benchmark {
    …
}

and added the following code to your build.gradle:

plugins {
    id 'org.jetbrains.kotlin.plugin.allopen'
}

allOpen {
    annotation("org.openjdk.jmh.annotations.State")
}

then you don't have to make benchmark classes and methods open.

Runtime Library

You need a runtime library with annotations and code that will run benchmarks.

Enable Maven Central for dependencies lookup:

repositories {
    mavenCentral()
}

Add the runtime to dependencies of the platform source set, e.g.:

kotlin {
    sourceSets {
        commonMain {
             dependencies {
                 implementation("org.jetbrains.kotlinx:kotlinx-benchmark-runtime:0.3.0")
             }
        }
    }
}

Configuration

In a build.gradle file create benchmark section, and inside it add a targets section. In this section register all targets you want to run benchmarks from. Example for multiplatform project:

benchmark {
    targets {
        register("jvm") 
        register("js")
        register("native")
    }
}

This package can also be used for Java and Kotlin/JVM projects. Register a Java sourceSet as a target:

benchmark {
    targets {
        register("main") 
    }
}

To configure benchmarks and create multiple profiles, create a configurations section in the benchmark block, and place options inside. Toolkit creates main configuration by default, and you can create as many additional configurations, as you need.

benchmark {
    configurations {
        main { 
            // configure default configuration
        }
        smoke { 
            // create and configure "smoke" configuration, e.g. with several fast benchmarks to quickly check
            // if code changes result in something very wrong, or very right. 
        }       
    }
}

Available configuration options:

• iterations – number of measuring iterations
• warmups – number of warm up iterations
• iterationTime – time to run each iteration (measuring and warmup)
• iterationTimeUnit – time unit for iterationTime (default is seconds)
• outputTimeUnit – time unit for results output
• mode – "thrpt" for measuring operations per time, or "avgt" for measuring time per operation
• include("…") – regular expression to include benchmarks with fully qualified names matching it, as a substring
• exclude("…") – regular expression to exclude benchmarks with fully qualified names matching it, as a substring
• param("name", "value1", "value2") – specify a parameter for a public mutable property name annotated with @Param
• reportFormat – format of report, can be json(default), csv, scsv or text

Time units can be NANOSECONDS, MICROSECONDS, MILLISECONDS, SECONDS, MINUTES, or their short variants such as "ms" or "ns".

Example:

benchmark {
    // Create configurations
    configurations {
        main { // main configuration is created automatically, but you can change its defaults
            warmups = 20 // number of warmup iterations
            iterations = 10 // number of iterations
            iterationTime = 3 // time in seconds per iteration
        }
        smoke {
            warmups = 5 // number of warmup iterations
            iterations = 3 // number of iterations
            iterationTime = 500 // time in seconds per iteration
            iterationTimeUnit = "ms" // time unity for iterationTime, default is seconds
        }   
    }
    
    // Setup targets
    targets {
        // This one matches compilation base name, e.g. 'jvm', 'jvmTest', etc
        register("jvm") {
            jmhVersion = "1.21" // available only for JVM compilations & Java source sets
        }
        register("js") {
            // Note, that benchmarks.js uses a different approach of minTime & maxTime and run benchmarks
            // until results are stable. We estimate minTime as iterationTime and maxTime as iterationTime*iterations
        }
        register("native")
    }
}

Separate source sets for benchmarks

Often you want to have benchmarks in the same project, but separated from main code, much like tests. Here is how:

Define source set:

sourceSets {
    benchmarks
}

Propagate dependencies and output from main sourceSet.

dependencies {
    benchmarksCompile sourceSets.main.output + sourceSets.main.runtimeClasspath 
}

You can also add output and compileClasspath from sourceSets.test in the same way if you want to reuse some of the test infrastructure.

Register benchmarks source set:

benchmark {
    targets {
        register("benchmarks")    
    }
}

Examples

The project contains examples subproject that demonstrates using the library.