child_process: reduce nextTick() usage

PR-URL: #13459 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

Author: mscdex

benchmark/cluster/echo.js

@@ -0,0 +1,70 @@
+'use strict';
+
+const cluster = require('cluster');
+if (cluster.isMaster) {
+ const common = require('../common.js');
+ const bench = common.createBenchmark(main, {
+ workers: [1],
+ payload: ['string', 'object'],
+ sendsPerBroadcast: [1, 10],
+ n: [1e5]
+ });
+
+ function main(conf) {
+ var n = +conf.n;
+ var workers = +conf.workers;
+ var sends = +conf.sendsPerBroadcast;
+ var expectedPerBroadcast = sends * workers;
+ var payload;
+ var readies = 0;
+ var broadcasts = 0;
+ var msgCount = 0;
+
+ switch (conf.payload) {
+ case 'string':
+ payload = 'hello world!';
+ break;
+ case 'object':
+ payload = { action: 'pewpewpew', powerLevel: 9001 };
+ break;
+ default:
+ throw new Error('Unsupported payload type');
+ }
+
+ for (var i = 0; i < workers; ++i)
+ cluster.fork().on('online', onOnline).on('message', onMessage);
+
+ function onOnline(msg) {
+ if (++readies === workers) {
+ bench.start();
+ broadcast();
+ }
+ }
+
+ function broadcast() {
+ var id;
+ if (broadcasts++ === n) {
+ bench.end(n);
+ for (id in cluster.workers)
+ cluster.workers[id].disconnect();
+ return;
+ }
+ for (id in cluster.workers) {
+ const worker = cluster.workers[id];
+ for (var i = 0; i < sends; ++i)
+ worker.send(payload);
+ }
+ }
+
+ function onMessage(msg) {
+ if (++msgCount === expectedPerBroadcast) {
+ msgCount = 0;
+ broadcast();
+ }
+ }
+ }
+} else {
+ process.on('message', function(msg) {
+ process.send(msg);
+ });
+}

lib/internal/child_process.js

@@ -456,16 +456,22 @@ function setupChannel(target, channel) {
  }
  chunks[0] = jsonBuffer + chunks[0];
 
+ var nextTick = false;
  for (var i = 0; i < numCompleteChunks; i++) {
  var message = JSON.parse(chunks[i]);
 
  // There will be at most one NODE_HANDLE message in every chunk we
  // read because SCM_RIGHTS messages don't get coalesced. Make sure
  // that we deliver the handle with the right message however.
- if (message && message.cmd === 'NODE_HANDLE')
- handleMessage(target, message, recvHandle);
- else
- handleMessage(target, message, undefined);
+ if (isInternal(message)) {
+ if (message.cmd === 'NODE_HANDLE')
+ handleMessage(message, recvHandle, true, false);
+ else
+ handleMessage(message, undefined, true, false);
+ } else {
+ handleMessage(message, undefined, false, nextTick);
+ nextTick = true;
+ }
  }
  jsonBuffer = incompleteChunk;
  this.buffering = jsonBuffer.length !== 0;
@@ -526,7 +532,7 @@ function setupChannel(target, channel) {
 
  // Convert handle object
  obj.got.call(this, message, handle, function(handle) {
- handleMessage(target, message.msg, handle);
+ handleMessage(message.msg, handle, isInternal(message.msg), false);
  });
  });
 
@@ -732,27 +738,32 @@ function setupChannel(target, channel) {
  process.nextTick(finish);
  };
 
+ function emit(event, message, handle) {
+ target.emit(event, message, handle);
+ }
+
+ function handleMessage(message, handle, internal, nextTick) {
+ if (!target.channel)
+ return;
+
+ var eventName = (internal ? 'internalMessage' : 'message');
+ if (nextTick)
+ process.nextTick(emit, eventName, message, handle);
+ else
+ target.emit(eventName, message, handle);
+ }
+
  channel.readStart();
  return control;
 }
 
-
 const INTERNAL_PREFIX = 'NODE_';
-function handleMessage(target, message, handle) {
- if (!target.channel)
- return;
-
- var eventName = 'message';
- if (message !== null &&
- typeof message === 'object' &&
- typeof message.cmd === 'string' &&
- message.cmd.length > INTERNAL_PREFIX.length &&
- message.cmd.slice(0, INTERNAL_PREFIX.length) === INTERNAL_PREFIX) {
- eventName = 'internalMessage';
- }
- process.nextTick(() => {
- target.emit(eventName, message, handle);
- });
+function isInternal(message) {
+ return (message !== null &&
+ typeof message === 'object' &&
+ typeof message.cmd === 'string' &&
+ message.cmd.length > INTERNAL_PREFIX.length &&
+ message.cmd.slice(0, INTERNAL_PREFIX.length) === INTERNAL_PREFIX);
 }
 
 function nop() { }