Add measure tracing API

[MonicaOlejniczak]

↪️ Pull Request

This change is similar to #9622 but instead introduces non-breaking changes that:

• Introduce a more flexible createTraceMeasurement API, by only instantiating relevant event data when tracing is enabled at the consumer side
• Add testing to prevent consumers from ending a measurement, using a new traceStart event

Additionally, some arguments have been updated to be more meaningful.

💻 Examples

N/A

🚨 Test instructions

Run with tracing enabled

[mattcompiles]

This also used to track bundle type as well. Did you intend to drop that?

[MonicaOlejniczak]

Nope, will add it back in. Thanks for picking that up

[marcins]

The original reasoning for having an API that didn't involve passing an object was to avoid the overhead of unnecessary object allocation in the case when tracing was disabled (which is most of the time).

Have you checked that the impact of performance on builds with tracing disabled of this change? Does timing/memory usage look okay? I just want to make sure we're not introducing unnecessary GC thrashing that might affect builds the size of Jira's.

[MonicaOlejniczak]

I created a crude benchmark that can be run with node --trace-gc --trace-gc_verbose test.mjs with this, commenting in one test at a time. I will revert the existing change so that it uses something more performant with more flexibility.

let enabled = false;

class Measurement {
  constructor(args) {
    this.args = args;
    this.start = performance.now();
  }

  end() {
    const end = performance.now();

    // tracer.trace();
  }
}

async function measure(args, fn) {
  if (!enabled) {
    return fn();
  }

  const measurement = new Measurement(args);
  let result;
  try {
    result = await fn();
  } finally {
    measurement.end();
  }

  return result;
}

for (let i = 0; i < 100_000_000; i++) {
  // fastest -> slowest
  await measure('world', async () => {});
  // await measure(enabled && { hello: 'world' }, async () => {});
  // await measure(enabled ? { hello: 'world' } : null, async () => {});
  // await measure({ hello: 'world' }, async () => {});
  // await measure(() => ({ hello: 'world' }), async () => {});
  // await measure({ get hello() { return 'world' }}, async () => {});
}

// for (let i = 0; i < 1_000_000_000; i++) {
//   measure({ hello: 'world' }, () => {});
//   measure('world', () => {});
// }

[marcins]

I know moving this check to the consumer avoids the function call at all, but is the only reason to change the create signature from individual params to an object? I'm still not sure what the benefit is apart from the naming?

[MonicaOlejniczak]

It's the naming and flexibility mostly, yeah