test-v8-cpu-profile.js

'use strict';

const common = require('../common');
const assert = require('assert');
const v8 = require('v8');

function busyLoop(iterations = 1000) {
  let total = 0;
  for (let i = 0; i < iterations; i++) {
    total += Math.sqrt(i + total);
  }
  return total;
}

function burnBlocks(blocks = 200, iterations = 1000) {
  let total = 0;
  for (let i = 0; i < blocks; i++) {
    total += busyLoop(iterations);
  }
  return total;
}

function collectProfile(options, workload) {
  const handle = v8.startCpuProfile(options);
  workload();
  return JSON.parse(handle.stop());
}

{
  const profile = collectProfile({ sampleInterval: 0.001 }, () => burnBlocks(400, 2000));
  assert.ok(profile.samples.length >= 1);
}

{
  const profile = collectProfile({ sampleInterval: 0.5, maxBufferSize: 3 }, () => burnBlocks(400, 2000));
  assert.ok(profile.samples.length <= 3);
}

{
  const profile = collectProfile({ sampleInterval: 0.1, maxBufferSize: 50 }, () => burnBlocks(600, 3000));
  assert.ok(profile.samples.length >= 1);
  assert.ok(profile.samples.length <= 50);
}

{
  assert.throws(
    () => v8.startCpuProfile({ sampleInterval: -1 }),
    common.expectsError({ code: 'ERR_OUT_OF_RANGE' }));
}