Support benchmark warmup with useWorkers=true

lib/index.js

@@ -259,7 +259,7 @@ class Suite {
 		}
 
 		// It doesn't make sense to warmup a fresh new instance of Worker.
-		// TODO: support warmup directly in the Worker.
+		// TODO: Should this be folded into the main loop?
 		if (!this.#useWorkers) {
 			// This is required to avoid variance on first benchmark run
 			for (let i = 0; i < this.#benchmarks.length; ++i) {

lib/worker-runner.js

@@ -1,5 +1,10 @@
 const { parentPort } = require("node:worker_threads");
-const { runBenchmark } = require("./lifecycle");
+const {
+	runBenchmark,
+	getInitialIterations,
+	runWarmup,
+} = require("./lifecycle");
+const { debugBench } = require("./clock");
 const AsyncFunction = Object.getPrototypeOf(async () => {}).constructor;
 
 // Deserialize the benchmark function
@@ -24,6 +29,16 @@ parentPort.on(
 		minSamples,
 	}) => {
 		deserializeBenchmark(benchmark);
+
+		debugBench(
+			`Warmup ${benchmark.name} with minTime=${benchmark.minTime}, maxTime=${benchmark.maxTime}`,
+		);
+		const initialIteration = await getInitialIterations(benchmark);
+		await runWarmup(benchmark, initialIteration, {
+			minTime: 0.005,
+			maxTime: 0.05,
+		});
+
 		const result = await runBenchmark(
 			benchmark,
 			initialIterations,