JMH benchmark setup

gradle.properties

@@ -3,4 +3,4 @@ org.gradle.configureondemand=false
 org.gradle.jvmargs=-XX:MaxMetaspaceSize=768m
 localrepo=build/mockk-repo
 # localrepo=/Users/raibaz/.m2/repository
-# kotlin.version=1.5.10
+kotlin.version=1.5.31

mockk/performance/README.md

@@ -0,0 +1,29 @@
+This is a performance testing setup for `mockk` using [JMH](https://github.com/openjdk/jmh). [kotlinx-benchmark](https://github.com/Kotlin/kotlinx-benchmark) seems to support more than JVM, but I didn't explore other runtimes.
+
+How to run
+==========
+There are 2 ways to execute the benchmark code
+
+Basic with Gradle
+-----------------
+
+```shell
+gradle benchmark
+```
+It will use default configuration set in  [build.gradle.kts](./build.gradle.kts) and print
+out the results
+
+Advanced with JMH binary
+------------------------
+
+If you want access to more JMH feautres you can 
+```shell
+gradle mainBenchmarkJar
+```
+to build the `.jar` file containing the benchamrk code. It will be saved to `./build/benchmarks/main/jars` directory.
+
+From there you can run JMH with all the JMH-specific configuration options form CLI (even on different machine).
+```shell
+java -jar ./build/benchmarks/main/jars/mockk-performance-main-jmh-<version>.jar -w 1 -i 2 -r 60s  -prof jfr
+```
+which will e.g. attach the JFR profiler (not possible with `kontlinx-benchmark` executed from Gradle)

mockk/performance/build.gradle.kts

@@ -0,0 +1,32 @@
+import kotlinx.benchmark.gradle.JvmBenchmarkTarget
+import kotlinx.benchmark.gradle.benchmark
+
+plugins {
+    java
+    kotlin("jvm")
+    id("org.jetbrains.kotlinx.benchmark") version "0.4.0"
+
+}
+
+dependencies {
+    implementation("org.jetbrains.kotlinx:kotlinx-benchmark-runtime:0.4.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.2")
+    implementation(project(":mockk-jvm"))
+}
+
+benchmark {
+    configurations {
+        named("main") {
+            iterationTime = 60
+            iterationTimeUnit = "sec"
+            iterations = 2
+            warmups = 1
+        }
+    }
+    targets {
+        register("main") {
+            this as JvmBenchmarkTarget
+            jmhVersion = "1.33"
+        }
+    }
+}

mockk/performance/src/main/kotlin/io/mockk/performance/JmhTest.kt

@@ -0,0 +1,23 @@
+package io.mockk.performance
+
+import io.mockk.every
+import io.mockk.mockk
+import org.openjdk.jmh.annotations.Benchmark
+import org.openjdk.jmh.annotations.BenchmarkMode
+import org.openjdk.jmh.annotations.Mode
+import org.openjdk.jmh.infra.Blackhole
+
+@BenchmarkMode(Mode.Throughput)
+open class JmhTest {
+
+    @Benchmark
+    fun simpleMockAndStub(blackhole: Blackhole) {
+        val mockedClass: MockedClass = mockk()
+        every { mockedClass.mockedFun() } returns "Hello, mockk!"
+        blackhole.consume(mockedClass)
+    }
+
+    class MockedClass {
+        fun mockedFun(): String = "Hello, world!"
+    }
+}

settings.gradle.kts

@@ -14,6 +14,7 @@ includeBuild("plugins/configuration")
 
 include("mockk-jvm")
 include("mockk-common")
+include("mockk-performance")
 //include 'mockk-js'
 
 val hasAndroidSdk = extra["hasAndroidSdk"]
@@ -42,6 +43,7 @@ if (hasAndroidSdk == true) project(":mockk-android").projectDir = file("mockk/an
 project(":mockk-agent-api").projectDir = file("agent/api")
 project(":mockk-agent-common").projectDir = file("agent/common")
 project(":mockk-agent-jvm").projectDir = file("agent/jvm")
+project(":mockk-performance").projectDir = file("mockk/performance")
 if (hasAndroidSdk == true) {
     project(":mockk-agent-android").projectDir = file("agent/android")
     project(":mockk-agent-android-dispatcher").projectDir = file("agent/android/dispatcher")