gc performance entries report incorrect startTime

[amilajack]

Version

v17.9.0

Platform

Darwin Amilas-MacBook-Pro.local 21.4.0 Darwin Kernel Version 21.4.0: Fri Mar 18 00:45:05 PDT 2022; root:xnu-8020.101.4~15/RELEASE_X86_64 x86_64

Subsystem

No response

What steps will reproduce the bug?

All performance entries' startTime should be relative to performance.timeOrigin.

repro:

import { PerformanceObserver } from "perf_hooks";

const formatTime = (ms) => new Date(ms).toLocaleString();

console.log(`time origin: ${formatTime(performance.timeOrigin)}`);

// observe mark and gc entries
const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach(({ entryType, startTime }) => {
    // gc performance entries aren't relative to timeOrigin
    console.log(entryType, formatTime(startTime + performance.timeOrigin));
  });
});
observer.observe({
  entryTypes: ["mark", "gc"],
});

// Mark entries are relative to timeOrigin
performance.mark("foo");

// Create some objects
setInterval(() => {
  const arr = new Array(1_000_000).fill(0);
  for (let i = 0; i < arr.length; i++) {
    arr[i] += 1;
  }
}, 1_000);

output:

time origin: 5/11/2022, 11:07:35 AM # correct
mark 5/11/2022, 11:07:35 AM            # correct
gc 5/20/2022, 10:23:36 AM              # incorrect
gc 5/20/2022, 10:23:36 AM              # incorrect
gc 5/20/2022, 10:23:37 AM              # incorrect
gc 5/20/2022, 10:23:38 AM              # incorrect
gc 5/20/2022, 10:23:39 AM              # incorrect

I've created a repl.it reproducing the bug.

How often does it reproduce? Is there a required condition?

I can reproduce it 100% of the time.

What is the expected behavior?

All performance entries' startTime should be relative to performance.timeOrigin. This isn't the case for the gc entry.

What do you see instead?

the startTime of gc performance entries are off by hours (see example output)

Additional information

No response