benchmark: fix child-process-read on Windows

Under Windows 'ipc' communication requires the other process to format
its messages with 'IPC framing protocol'. Otherwise, an assert is
triggered in libuv. This commit changes child-process-read benchmark
to use stdout to communicate with parent process. It also adds
child-process-read-ipc.js to benchmark IPC communication using
child node process.

PR-URL: https://github.com/nodejs/node/pull/6971
Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

benchmark/child_process/child-process-read-ipc.js

@@ -0,0 +1,37 @@
+'use strict';
+if (process.argv[2] === 'child')
+{
+  const len = +process.argv[3];
+  const msg = `"${'.'.repeat(len)}"`;
+  while (true) {
+    process.send(msg);
+  }
+} else {
+  const common = require('../common.js');
+  const bench = common.createBenchmark(main, {
+    len: [64, 256, 1024, 4096, 32768],
+    dur: [5]
+  });
+  const spawn = require('child_process').spawn;
+  function main(conf) {
+    bench.start();
+
+    const dur = +conf.dur;
+    const len = +conf.len;
+
+    const options = { 'stdio': ['ignore', 'ignore', 'ignore', 'ipc'] };
+    const child = spawn(process.argv[0],
+      [process.argv[1], 'child', len], options);
+
+    var bytes = 0;
+    child.on('message', function(msg) {
+      bytes += msg.length;
+    });
+
+    setTimeout(function() {
+      child.kill();
+      const gbits = (bytes * 8) / (1024 * 1024 * 1024);
+      bench.end(gbits);
+    }, dur * 1000);
+  }
+}

benchmark/child_process/child-process-read.js

@@ -1,7 +1,14 @@
 'use strict';
 const common = require('../common.js');
+const os = require('os');
+
+var messagesLength = [64, 256, 1024, 4096];
+// Windows does not support that long arguments
+if (os.platform() !== 'win32')
+  messagesLength.push(32768);
+
 const bench = common.createBenchmark(main, {
-  len: [64, 256, 1024, 4096, 32768],
+  len: messagesLength,
   dur: [5]
 });
 
@@ -13,11 +20,11 @@ function main(conf) {
   const len = +conf.len;
 
   const msg = '"' + Array(len).join('.') + '"';
-  const options = {'stdio': ['ignore', 'ipc', 'ignore']};
+  const options = { 'stdio': ['ignore', 'pipe', 'ignore'] };
   const child = spawn('yes', [msg], options);
 
   var bytes = 0;
-  child.on('message', function(msg) {
+  child.stdout.on('data', function(msg) {
     bytes += msg.length;
   });