benchmark: add benchmark for fsPromises.writeFile

added fs.promises.writeFile benchmark
PR-URL: #37610
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: Linkgoron

benchmark/fs/writefile-promises.js

@@ -0,0 +1,76 @@
+// Call fs.promises.writeFile over and over again really fast.
+// Then see how many times it got called.
+// Yes, this is a silly benchmark. Most benchmarks are silly.
+'use strict';
+
+constpath=require('path');
+constcommon=require('../common.js');
+constfs=require('fs');
+constassert=require('assert');
+consttmpdir=require('../../test/common/tmpdir');
+
+tmpdir.refresh();
+constfilename=path.resolve(tmpdir.path,
+`.removeme-benchmark-garbage-${process.pid}`);
+letfilesWritten=0;
+constbench=common.createBenchmark(main,{
+duration: [5],
+encodingType: ['buf','asc','utf'],
+size: [2,1024,65535,1024*1024],
+concurrent: [1,10]
+});
+
+functionmain({ encodingType, duration, concurrent, size }){
+letencoding;
+letchunk;
+switch(encodingType){
+case'buf':
+chunk=Buffer.alloc(size,'b');
+break;
+case'asc':
+chunk='a'.repeat(size);
+encoding='ascii';
+break;
+case'utf':
+chunk='ü'.repeat(Math.ceil(size/2));
+encoding='utf8';
+break;
+default:
+thrownewError(`invalid encodingType: ${encodingType}`);
+}
+
+letwrites=0;
+letbenchEnded=false;
+bench.start();
+setTimeout(()=>{
+benchEnded=true;
+bench.end(writes);
+for(leti=0;i<filesWritten;i++){
+try{fs.unlinkSync(`${filename}-${i}`);}catch{}
+}
+process.exit(0);
+},duration*1000);
+
+functionwrite(){
+fs.promises.writeFile(`${filename}-${filesWritten++}`,chunk,encoding)
+.then(()=>afterWrite())
+.catch((err)=>afterWrite(err));
+}
+
+functionafterWrite(er){
+if(er){
+if(er.code==='ENOENT'){
+// Only OK if unlinked by the timer from main.
+assert.ok(benchEnded);
+return;
+}
+thrower;
+}
+
+writes++;
+if(!benchEnded)
+write();
+}
+
+while(concurrent--)write();
+}