lib: make queueMicrotask faster

No longer create an additional scope within queueMicrotask
in order to improve performance.

PR-URL: #27032
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>

benchmark/process/queue-microtask-breadth.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const common = require('../common.js');
+const bench = common.createBenchmark(main, {
+  n: [4e5]
+});
+
+function main({ n }) {
+  var j = 0;
+
+  function cb() {
+    j++;
+    if (j === n)
+      bench.end(n);
+  }
+
+  bench.start();
+  for (var i = 0; i < n; i++) {
+    queueMicrotask(cb);
+  }
+}

benchmark/process/queue-microtask-depth.js

@@ -0,0 +1,17 @@
+'use strict';
+const common = require('../common.js');
+const bench = common.createBenchmark(main, {
+  n: [12e5]
+});
+
+function main({ n }) {
+  let counter = n;
+  bench.start();
+  queueMicrotask(onNextTick);
+  function onNextTick() {
+    if (--counter)
+      queueMicrotask(onNextTick);
+    else
+      bench.end(n);
+  }
+}

lib/internal/process/task_queues.js

@@ -37,6 +37,8 @@ const {
 } = require('internal/errors').codes;
 const FixedQueue = require('internal/fixed_queue');
 
+const FunctionBind = Function.call.bind(Function.prototype.bind);
+
 // *Must* match Environment::TickInfo::Fields in src/env.h.
 const kHasTickScheduled = 0;
 
@@ -149,28 +151,32 @@ function createMicrotaskResource() {
   });
 }
 
+function runMicrotask() {
+  this.runInAsyncScope(() => {
+    const callback = this.callback;
+    try {
+      callback();
+    } catch (error) {
+      // TODO(devsnek) remove this if
+      // https://bugs.chromium.org/p/v8/issues/detail?id=8326
+      // is resolved such that V8 triggers the fatal exception
+      // handler for microtasks
+      triggerFatalException(error);
+    } finally {
+      this.emitDestroy();
+    }
+  });
+}
+
 function queueMicrotask(callback) {
   if (typeof callback !== 'function') {
     throw new ERR_INVALID_ARG_TYPE('callback', 'function', callback);
   }
 
   const asyncResource = createMicrotaskResource();
+  asyncResource.callback = callback;
 
-  enqueueMicrotask(() => {
-    asyncResource.runInAsyncScope(() => {
-      try {
-        callback();
-      } catch (error) {
-        // TODO(devsnek) remove this if
-        // https://bugs.chromium.org/p/v8/issues/detail?id=8326
-        // is resolved such that V8 triggers the fatal exception
-        // handler for microtasks
-        triggerFatalException(error);
-      } finally {
-        asyncResource.emitDestroy();
-      }
-    });
-  });
+  enqueueMicrotask(FunctionBind(runMicrotask, asyncResource));
 }
 
 module.exports = {