node.js memory, cpu, gc

test1.js

var SlowBuffer = require('buffer').SlowBuffer;
var ITER = 1e5, SIZE = 65536, cntr = 0;
var t = process.hrtime();

(function runner() {
  if (++cntr > ITER) return print();
  new SlowBuffer(SIZE);
  setImmediate(runner);
}());

function print() {
  t = process.hrtime(t);
  console.log(((t[0] * 1e9 + t[1]) / ITER).toFixed(1) + ' ns/op');
}

test2.js

'use strict';

var limit = 1000000;
var concurrent = 20;
var scavenges = true;

var warmup = limit / 10;
var start, count = 0;
limit += warmup;

function call() {
    var buffer = new Buffer(64 * 1024);
    var bufferx;
    if (scavenges && (count % 170 === 0)) {
        // gc(true) is a scavenge. Not sure if this is documented.
        gc(true);
    }
    count++;
    if (count > limit) {
        console.log(process.hrtime(start));
        process.exit(0);
    } else if (count === warmup) {
        start = process.hrtime();
    }
    setImmediate(call);
}

for (var i = 0; i < concurrent; i++) {
    call();
}