bench: Add fs write stream throughput

benchmark/fs/write-stream-throughput.js

@@ -0,0 +1,78 @@
+// test the througput of the fs.WriteStream class.
+
+var path = require('path');
+var common = require('../common.js');
+var filename = path.resolve(__dirname, '.removeme-benchmark-garbage');
+var fs = require('fs');
+
+var bench = common.createBenchmark(main, {
+  dur: [1, 3],
+  type: ['buf', 'asc', 'utf'],
+  size: [2, 1024, 65535, 1024 * 1024]
+});
+
+function main(conf) {
+  var dur = +conf.dur;
+  var type = conf.type;
+  var size = +conf.size;
+  var encoding;
+
+  var chunk;
+  switch (type) {
+    case 'buf':
+      chunk = new Buffer(size);
+      chunk.fill('b');
+      break;
+    case 'asc':
+      chunk = new Array(size + 1).join('a');
+      encoding = 'ascii';
+      break;
+    case 'utf':
+      chunk = new Array(Math.ceil(size/2) + 1).join('ü');
+      encoding = 'utf8';
+      break;
+    default:
+      throw new Error('invalid type');
+  }
+
+  try { fs.unlinkSync(filename); } catch (e) {}
+
+  var started = false;
+  var ending = false;
+  var ended = false;
+  setTimeout(function() {
+    ending = true;
+    f.end();
+  }, dur * 1000);
+
+  var f = fs.createWriteStream(filename);
+  f.on('drain', write);
+  f.on('open', write);
+  f.on('close', done);
+  f.on('finish', function() {
+    ended = true;
+    var written = fs.statSync(filename).size / 1024;
+    try { fs.unlinkSync(filename); } catch (e) {}
+    bench.end(written / 1024);
+  });
+
+
+  function write() {
+    // don't try to write after we end, even if a 'drain' event comes.
+    // v0.8 streams are so sloppy!
+    if (ending)
+      return;
+
+    if (!started) {
+      started = true;
+      bench.start();
+    }
+
+    while (false !== f.write(chunk, encoding));
+  }
+
+  function done() {
+    if (!ended)
+      f.emit('finish');
+  }
+}