draft: some exploration about performance of execSync

lib/child_process.js

@@ -91,6 +91,7 @@ const {
   ChildProcess,
   stdioStringToArray,
 } = child_process;
+const perf_hooks = require('perf_hooks');
 
 const MAX_BUFFER = 1024 * 1024;
 
@@ -825,10 +826,13 @@ function spawn(file, args, options) {
  *   }}
  */
 function spawnSync(file, args, options) {
+  let now = perf_hooks.performance.now();
   options = {
     maxBuffer: MAX_BUFFER,
     ...normalizeSpawnArguments(file, args, options),
   };
+  console.log(`execSync spawnSync > normalizeSpawnArguments: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
 
   debug('spawnSync', options);
 
@@ -838,9 +842,15 @@ function spawnSync(file, args, options) {
   // Validate maxBuffer, if present.
   validateMaxBuffer(options.maxBuffer);
 
+  console.log(`execSync spawnSync > validation: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
+
   // Validate and translate the kill signal, if present.
   options.killSignal = sanitizeKillSignal(options.killSignal);
 
+  console.log(`execSync spawnSync > sanitizeKillSignal: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
+
   options.stdio = getValidStdio(options.stdio || 'pipe', true).stdio;
 
   if (options.input) {
@@ -868,7 +878,12 @@ function spawnSync(file, args, options) {
     }
   }
 
-  return child_process.spawnSync(options);
+  console.log(`execSync spawnSync > stdio & input: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
+  const result = child_process.spawnSync(options);
+  console.log(`execSync spawnSync > child_process.spawnSync: ${perf_hooks.performance.now() - now}`);
+
+  return result;
 }
 
 
@@ -946,16 +961,27 @@ function execFileSync(file, args, options) {
  * @returns {Buffer | string}
  */
 function execSync(command, options) {
+  let now = perf_hooks.performance.now();
   const opts = normalizeExecArgs(command, options, null);
+  console.log(`execSync normalizeExecArgs: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
   const inheritStderr = !opts.options.stdio;
 
   const ret = spawnSync(opts.file, opts.options);
+  console.log(`execSync spawnSync: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
 
   if (inheritStderr && ret.stderr)
     process.stderr.write(ret.stderr);
 
+  console.log(`execSync inheritStderr: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
+
   const err = checkExecSyncError(ret, undefined, command);
 
+  console.log(`execSync checkExecSyncError: ${perf_hooks.performance.now() - now}`);
+  now = perf_hooks.performance.now();
+
   if (err)
     throw err;