benchmark: improve module-loader benchmark

Add more benchmark options to properly verify the gains.

This makes sure the benchmark also tests requiring the same module
again instead of only loading each module only once.

PR-URL: nodejs#26970
Refs: nodejs#25362
Reviewed-By: Guy Bedford <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>

benchmark/module/module-loader.js

@@ -1,21 +1,27 @@
 'use strict';
 const fs = require('fs');
 const path = require('path');
+const { builtinModules } = require('module');
 const common = require('../common.js');
 
 const tmpdir = require('../../test/common/tmpdir');
-const benchmarkDirectory = path.join(tmpdir.path, 'nodejs-benchmark-module');
+let benchmarkDirectory = path.join(tmpdir.path, 'nodejs-benchmark-module');
+
+// Filter all irregular modules.
+const otherModules = builtinModules.filter((name) => !/\/|^_|^sys/.test(name));
 
 const bench = common.createBenchmark(main, {
-  n: [5e4],
-  fullPath: ['true', 'false'],
-  useCache: ['true', 'false']
+  name: ['', '/', '/index.js'],
+  dir: ['rel', 'abs'],
+  files: [5e2],
+  n: [1, 1e3],
+  cache: ['true', 'false']
 });
 
-function main({ n, fullPath, useCache }) {
+function main({ n, name, cache, files, dir }) {
   tmpdir.refresh();
-  try { fs.mkdirSync(benchmarkDirectory); } catch {}
-  for (var i = 0; i <= n; i++) {
+  fs.mkdirSync(benchmarkDirectory);
+  for (var i = 0; i <= files; i++) {
     fs.mkdirSync(`${benchmarkDirectory}${i}`);
     fs.writeFileSync(
       `${benchmarkDirectory}${i}/package.json`,
@@ -27,38 +33,28 @@ function main({ n, fullPath, useCache }) {
     );
   }
 
-  if (fullPath === 'true')
-    measureFull(n, useCache === 'true');
-  else
-    measureDir(n, useCache === 'true');
+  if (dir === 'rel')
+    benchmarkDirectory = path.relative(__dirname, benchmarkDirectory);
 
-  tmpdir.refresh();
-}
+  measureDir(n, cache === 'true', files, name);
 
-function measureFull(n, useCache) {
-  var i;
-  if (useCache) {
-    for (i = 0; i <= n; i++) {
-      require(`${benchmarkDirectory}${i}/index.js`);
-    }
-  }
-  bench.start();
-  for (i = 0; i <= n; i++) {
-    require(`${benchmarkDirectory}${i}/index.js`);
-  }
-  bench.end(n);
+  tmpdir.refresh();
 }
 
-function measureDir(n, useCache) {
+function measureDir(n, cache, files, name) {
   var i;
-  if (useCache) {
-    for (i = 0; i <= n; i++) {
-      require(`${benchmarkDirectory}${i}`);
+  if (cache) {
+    for (i = 0; i <= files; i++) {
+      require(`${benchmarkDirectory}${i}${name}`);
     }
   }
   bench.start();
-  for (i = 0; i <= n; i++) {
-    require(`${benchmarkDirectory}${i}`);
+  for (i = 0; i <= files; i++) {
+    for (var j = 0; j < n; j++)
+      require(`${benchmarkDirectory}${i}${name}`);
+    // Pretend mixed input (otherwise the results are less representative due to
+    // highly specialized code).
+    require(otherModules[i % otherModules.length]);
   }
-  bench.end(n);
+  bench.end(n * files);
 }