benchmark: add per-suite setup option

This allows us to set up fixtures for the benchmark suite only
once, which can save quite a bit of time when running benchmarks
that require tens of thousands of fixture files or more (e.g.
the module benchmarks).
PR-URL: #60574Fixes: #58488
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

Author: joyeecheung

benchmark/common.js

@@ -28,6 +28,7 @@ class Benchmark {
 constargv=process.argv.slice(2);
 constparsed_args=this._parseArgs(argv,configs,options);
 
+this.originalOptions=options;
 this.options=parsed_args.cli;
 this.extra_options=parsed_args.extra;
 this.combinationFilter=typeofoptions.combinationFilter==='function' ? options.combinationFilter : allow;
@@ -207,6 +208,12 @@ class Benchmark {
 });
 }
 
+if(this.originalOptions.setup){
+// Only do this from the root process. _run() is only ever called from the root,
+// in child processes main is run directly.
+this.originalOptions.setup(this.queue);
+}
+
 constrecursive=(queueIndex)=>{
 constconfig=this.queue[queueIndex];
 

benchmark/module/module-require.js

@@ -8,12 +8,15 @@ const benchmarkDirectory = tmpdir.resolve('nodejs-benchmark-module');
 constbench=common.createBenchmark(main,{
 type: ['.js','.json','dir'],
 n: [1e4],
+},{
+setup(configs){
+tmpdir.refresh();
+constmaxN=configs.reduce((max,c)=>Math.max(max,c.n),0);
+createEntryPoint(maxN);
+},
 });
 
 functionmain({ type, n }){
-tmpdir.refresh();
-createEntryPoint(n);
-
 switch(type){
 case'.js':
 measureJSFile(n);
@@ -24,8 +27,6 @@ function main({ type, n }) {
 case'dir':
 measureDir(n);
 }
-
-tmpdir.refresh();
 }
 
 functionmeasureJSFile(n){

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

@@ -591,6 +591,32 @@ The arguments of `createBenchmark` are:
  containing a combination of benchmark parameters. It should return`true`
  or `false` to indicate whether the combination should be included or not.
 
+*`setup` {Function} Afunction that will be run once in the root process
+ before the benchmark combinations are executed in child processes.
+ It can be used to setup any global state required by the benchmark. Note
+ that the JavaScript heap state will not be shared with the benchmark processes,
+ so don't try to access any variables created in the `setup` function from
+ the `main` function, for example.
+ The argument passed into it is an array of all the combinations of
+ configurations that will be executed.
+ If tear down is necessary, register a listener for the `exit` event on
+ `process` inside the `setup` function. In the example below, that's done
+ by `tmpdir.refresh()`.
+
+ ```js
+ const tmpdir = require('../../test/common/tmpdir');
+ const bench = common.createBenchmark(main, {
+ type: ['fast', 'slow'],
+ n: [1e4],
+ }, {
+setup(configs) {
+tmpdir.refresh();
+constmaxN=configs.reduce((max, c) =>Math.max(max, c.n), 0);
+setupFixturesReusedForAllBenchmarks(maxN);
+ },
+ });
+ ```
+
 `createBenchmark` returns a `bench` object, which is used for timing
 the runtime of the benchmark. Run`bench.start()` after the initialization
 and `bench.end(n)` when the benchmark is done. `n` is the number of operations