For some reason, console.time and console.timeEnd, just work inside scope of function fs.readFile: Original: ```javascript console.time('file'); var thread = 1; var count = 1; while(count <= 6) { fs.readFile('./file.mov', function (err, data) { console.log("Thread #" + thread++ + " finish"); console.timeEnd('file'); }); count++; } ``` My: ```javascript var thread = 1; var count = 1; while(count <= 6) { fs.readFile('./imagem.iso', function (err, data) { console.time('file'); console.log("Thread #" + thread++ + " finish"); console.timeEnd('file'); }); count++; } ``` My node version v6.11.2