Merge branch 'new-channels-select' of github.com:Kotlin/kotlinx.coroutines into new-channels-select

Author: Nikita Koval

benchmarks/src/jmh/kotlin/benchmarks/tailcall/SelectBenchmark.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2016-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package benchmarks.tailcall
+
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.*
+import kotlinx.coroutines.selects.*
+import org.openjdk.jmh.annotations.*
+import java.util.concurrent.*
+
+@Warmup(iterations = 8, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 8, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(value = 1)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@State(Scope.Benchmark)
+open class SelectBenchmark {
+    // 450
+    private val iterations = 1000
+
+    @Benchmark
+    fun stressSelect() = runBlocking {
+        val pingPong = Channel<Unit>()
+        launch {
+            repeat(iterations) {
+                select {
+                    pingPong.onSend(Unit) {}
+                }
+            }
+        }
+
+        launch {
+            repeat(iterations) {
+                select {
+                    pingPong.onReceive() {}
+                }
+            }
+        }
+    }
+}