benchmark: calibrate config array-vs-concat

According to nodejs/performance#186
this benchmark was taking 160 secs for a single run.

Based on a research in a dedicated machine, the results
doesn't have variation based on the configs, so we don't
need to bench all variations.

Signed-off-by: RafaelGSS <rafael.nunu@hotmail.com>
PR-URL: nodejs#59587
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: RafaelGSS

benchmark/dgram/array-vs-concat.js

@@ -5,18 +5,18 @@ const common = require('../common.js');
 const dgram = require('dgram');
 const PORT = common.PORT;
 
-// `num` is the number of send requests to queue up each time.
+// `n` is the number of send requests to queue up each time.
 // Keep it reasonably high (>10) otherwise you're benchmarking the speed of
 // event loop cycles more than anything else.
 const bench = common.createBenchmark(main, {
-  len: [64, 256, 512, 1024],
-  num: [100],
-  chunks: [1, 2, 4, 8],
+  len: [64, 512, 1024],
+  n: [100],
+  chunks: [1, 4],
   type: ['concat', 'multi'],
   dur: [5],
 });
 
-function main({ dur, len, num, type, chunks }) {
+function main({ dur, len, n, type, chunks }) {
   const chunk = [];
   for (let i = 0; i < chunks; i++) {
     chunk.push(Buffer.allocUnsafe(Math.round(len / chunks)));
@@ -28,23 +28,23 @@ function main({ dur, len, num, type, chunks }) {
   const onsend = type === 'concat' ? onsendConcat : onsendMulti;
 
   function onsendConcat() {
-    if (sent++ % num === 0) {
+    if (sent++ % n === 0) {
       // The setImmediate() is necessary to have event loop progress on OSes
       // that only perform synchronous I/O on nonblocking UDP sockets.
       setImmediate(() => {
-        for (let i = 0; i < num; i++) {
+        for (let i = 0; i < n; i++) {
           socket.send(Buffer.concat(chunk), PORT, '127.0.0.1', onsend);
         }
       });
     }
   }
 
   function onsendMulti() {
-    if (sent++ % num === 0) {
+    if (sent++ % n === 0) {
       // The setImmediate() is necessary to have event loop progress on OSes
       // that only perform synchronous I/O on nonblocking UDP sockets.
       setImmediate(() => {
-        for (let i = 0; i < num; i++) {
+        for (let i = 0; i < n; i++) {
           socket.send(chunk, PORT, '127.0.0.1', onsend);
         }
       });