build.gradle

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath group: 'org.codehaus.groovy', name: 'groovy-json', version: '3.0.10'
    }
}

plugins {
    id "java"
    id "me.champeau.jmh" version "0.6.6"
}

group 'org.example'
version '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

jmh {
    resultFormat = 'JSON'
    jvmArgs = ['-XX:-TieredCompilation']
}

import groovy.json.JsonOutput
import groovy.json.JsonSlurper

task convertJmhResultForGithubActions {
    doLast {
        def jmhResults = project.file("${project.buildDir}/results/jmh/results.json")
        if (!jmhResults.exists()) {
            println 'Results does not exist'
            return
        }
        def ghActionData = new JsonSlurper().parse(jmhResults).collect { benchmark ->
            [
                    name : benchmark.benchmark,
                    value: benchmark.primaryMetric.score,
                    unit : benchmark.primaryMetric.scoreUnit,
                    extra: "iterations: ${benchmark.measurementIterations}\nforks: ${benchmark.forks}\nthreads: ${benchmark.threads}\nmode: ${benchmark.mode}"
            ]
        }
        project.file("${project.buildDir}/results/jmh/results-gh-benchmark.json").write(JsonOutput.toJson(ghActionData))
    }
    mustRunAfter "jmh"
}