benchmark: adds groups to better separate benchmarks

Fixes: https://github.com/nodejs/node/issues/26425
Co-Authored-By: Yaman Kassir <mestery@protonmail.com>
PR-URL: https://github.com/nodejs/node/pull/54393
Reviewed-By: Vinícius Lourenço Claro Cardoso <contact@viniciusl.com.br>

benchmark/common.js

@@ -22,27 +22,36 @@ class Benchmark {
     this.name = require.main.filename.slice(__dirname.length + 1);
 
     // Execution arguments i.e. flags used to run the jobs
-    this.flags = process.env.NODE_BENCHMARK_FLAGS ?
-      process.env.NODE_BENCHMARK_FLAGS.split(/\s+/) :
-      [];
+    this.flags = process.env.NODE_BENCHMARK_FLAGS?.split(/\s+/) ?? [];
 
     // Parse job-specific configuration from the command line arguments
     const argv = process.argv.slice(2);
     const parsed_args = this._parseArgs(argv, configs, options);
+
     this.options = parsed_args.cli;
     this.extra_options = parsed_args.extra;
+    this.combinationFilter = typeof options.combinationFilter === 'function' ? options.combinationFilter : allow;
+
+    if (options.byGroups) {
+      this.queue = [];
+      const groupNames = process.env.NODE_RUN_BENCHMARK_GROUPS?.split(',') ?? Object.keys(configs);
+
+      for (const groupName of groupNames) {
+        const config = { ...configs[groupName][0], group: groupName };
+        const parsed_args = this._parseArgs(argv, config, options);
+
+        this.options = parsed_args.cli;
+        this.extra_options = parsed_args.extra;
+        this.queue = this.queue.concat(this._queue(this.options));
+      }
+    } else {
+      this.queue = this._queue(this.options);
+    }
+
     if (options.flags) {
       this.flags = this.flags.concat(options.flags);
     }
 
-    if (typeof options.combinationFilter === 'function')
-      this.combinationFilter = options.combinationFilter;
-    else
-      this.combinationFilter = allow;
-
-    // The configuration list as a queue of jobs
-    this.queue = this._queue(this.options);
-
     if (this.queue.length === 0)
       return;
 

benchmark/http/headers.js

@@ -4,10 +4,22 @@ const common = require('../common.js');
 const http = require('http');
 
 const bench = common.createBenchmark(main, {
-  n: [10, 600],
-  len: [1, 100],
-  duration: 5,
-});
+  fewHeaders: {
+    n: [10],
+    len: [1, 5],
+    duration: 5,
+  },
+  mediumHeaders: {
+    n: [50],
+    len: [1, 10],
+    duration: 5,
+  },
+  manyHeaders: {
+    n: [600],
+    len: [1, 100],
+    duration: 5,
+  },
+}, { byGroups: true });
 
 function main({ len, n, duration }) {
   const headers = {
@@ -15,10 +27,9 @@ function main({ len, n, duration }) {
     'Transfer-Encoding': 'chunked',
   };
 
-  // TODO(BridgeAR): Change this benchmark to use grouped arguments when
-  // implemented. https://github.com/nodejs/node/issues/26425
-  const Is = [ ...Array(Math.max(n / len, 1)).keys() ];
-  const Js = [ ...Array(len).keys() ];
+  const Is = [...Array(n / len).keys()];
+  const Js = [...Array(len).keys()];
+
   for (const i of Is) {
     headers[`foo${i}`] = Js.map(() => `some header value ${i}`);
   }
@@ -27,6 +38,7 @@ function main({ len, n, duration }) {
     res.writeHead(200, headers);
     res.end();
   });
+
   server.listen(0, () => {
     bench.http({
       path: '/',

doc/contributing/writing-and-running-benchmarks.md

@@ -272,6 +272,19 @@ process/bench-env.js operation="query" n=1000000: 3,625,787.2150573144
 process/bench-env.js operation="delete" n=1000000: 1,521,131.5742806569
 ```
 
+#### Grouping benchmarks
+
+Benchmarks can also have groups, giving the developer greater flexibility in differentiating between test cases
+and also helping reduce the time to run the combination of benchmark parameters.
+
+By default, all groups are executed when running the benchmark.
+However, it is possible to specify individual groups by setting the
+`NODE_RUN_BENCHMARK_GROUPS` environment variable when running `compare.js`:
+
+```bash
+NODE_RUN_BENCHMARK_GROUPS=fewHeaders,manyHeaders node http/headers.js
+```
+
 ### Comparing Node.js versions
 
 To compare the effect of a new Node.js version use the `compare.js` tool. This
@@ -492,6 +505,23 @@ The arguments of `createBenchmark` are:
 * `options` {Object} The benchmark options. Supported options:
   * `flags` {Array} Contains node-specific command line flags to pass to
     the child process.
+
+  * `byGroups` {Boolean} option for processing `configs` by groups:
+    ```js
+    const bench = common.createBenchmark(main, {
+      groupA: {
+        source: ['array'],
+        len: [10, 2048],
+        n: [50],
+      },
+      groupB: {
+        source: ['buffer', 'string'],
+        len: [2048],
+        n: [50, 2048],
+      }
+    }, { byGroups: true });
+    ```
+
   * `combinationFilter` {Function} Has a single parameter which is an object
     containing a combination of benchmark parameters. It should return `true`
     or `false` to indicate whether the combination should be included or not.

test/common/benchmark.js

@@ -27,16 +27,27 @@ function runBenchmark(name, env) {
   child.on('exit', (code, signal) => {
     assert.strictEqual(code, 0);
     assert.strictEqual(signal, null);
+
     // This bit makes sure that each benchmark file is being sent settings such
     // that the benchmark file runs just one set of options. This helps keep the
-    // benchmark tests from taking a long time to run. Therefore, each benchmark
-    // file should result in three lines of output: a blank line, a line with
-    // the name of the benchmark file, and a line with the only results that we
-    // get from testing the benchmark file.
-    assert.ok(
-      /^(?:\n.+?\n.+?\n)+$/.test(stdout),
-      `benchmark file not running exactly one configuration in test: ${stdout}`,
-    );
+    // benchmark tests from taking a long time to run. Therefore, stdout should be composed as follows:
+    // The first and last lines should be empty.
+    // Each test should be separated by a blank line.
+    // The first line of each test should contain the test's name.
+    // The second line of each test should contain the configuration for the test.
+    // If the test configuration is not a group, there should be exactly two lines.
+    // Otherwise, it is possible to have more than two lines.
+
+    const splitTests = stdout.split(/\n\s*\n/);
+
+    for (let testIdx = 1; testIdx < splitTests.length - 1; testIdx++) {
+      const lines = splitTests[testIdx].split('\n');
+      assert.ok(/.+/.test(lines[0]));
+
+      if (!lines[1].includes('group="')) {
+        assert.strictEqual(lines.length, 2, `benchmark file not running exactly one configuration in test: ${stdout}`);
+      }
+    }
   });
 }