add benchmark for write and writeUtf8

src/Terminal.benchmark.ts

@@ -0,0 +1,75 @@
+import { perfContext, before, ThroughputRuntimeCase } from 'xterm-benchmark';
+
+import { Terminal } from 'Terminal';
+import { spawn } from 'node-pty';
+import { Utf8ToUtf32, stringFromCodePoint } from '../out/core/input/TextDecoder';
+
+
+class TestTerminal extends Terminal {
+  writeSync(data: string): void {
+    this.writeBuffer.push(data);
+    this._innerWrite();
+  }
+  writeSyncUtf8(data: Uint8Array): void {
+    this.writeBufferUtf8.push(data);
+    this._innerWriteUtf8();
+  }
+}
+
+perfContext('Terminal: ls -lR /usr', () => {
+  let content = '';
+  let contentUtf8: Uint8Array;
+
+  before(async () => {
+    // grab output from "ls -lR /usr"
+    const p = spawn('ls', ['--color=auto', '-lR', '/usr'], {
+      name: 'xterm-color',
+      cols: 80,
+      rows: 25,
+      cwd: process.env.HOME,
+      env: process.env,
+      encoding: null
+    });
+    const chunks: Buffer[] = [];
+    let length = 0;
+    p.on('data', data => {
+      chunks.push(data as unknown as Buffer);
+      length += data.length;
+    });
+    await new Promise(resolve => p.on('exit', () => resolve()));
+    contentUtf8 = Buffer.concat(chunks, length);
+    // translate to content string
+    const buffer = new Uint32Array(contentUtf8.length);
+    const decoder = new Utf8ToUtf32();
+    const codepoints = decoder.decode(contentUtf8, buffer);
+    for (let i = 0; i < codepoints; ++i) {
+      content += stringFromCodePoint(buffer[i]);
+      // peek into content to force flat repr in v8
+      if (!(i % 10000000)) {
+        content[i];
+      }
+    }
+  });
+
+  perfContext('write', () => {
+    let terminal: TestTerminal;
+    before(() => {
+      terminal = new TestTerminal({cols: 80, rows: 25, scrollback: 1000});
+    });
+    new ThroughputRuntimeCase('', () => {
+      terminal.writeSync(content);
+      return {payloadSize: contentUtf8.length};
+    }, {fork: false}).showAverageThroughput();
+  });
+
+  perfContext('writeUtf8', () => {
+    let terminal: TestTerminal;
+    before(() => {
+      terminal = new TestTerminal({cols: 80, rows: 25, scrollback: 1000});
+    });
+    new ThroughputRuntimeCase('', () => {
+      terminal.writeSyncUtf8(contentUtf8);
+      return {payloadSize: contentUtf8.length};
+    }, {fork: false}).showAverageThroughput();
+  });
+});