What is the Profiling Overhead in Performance

Question

I've seen that there is something called Profilling Overhead in Performance Timing. But currently I cannot find what does it mean. And What will effect the time of it. Is there anyone can help about it screenshot

Refresh for several times but every time has it.

Hoard

When running the profiler to measure the performance of your page the profiler itself takes a lot of CPU time. The Profiling Overhead is the extra load your page sees due to the fact that you're trying to measure performance, not because of anything your code does. – Jeffryjeffy

Answer 1

One of the major pieces of the Chrome DevTools Performance panel's instrumentation is the V8 Sampling Profiler, which provides the data about what JavaScript callstacks are active. That's exactly what builds the JavaScript parts of the flame chart.

The V8 Profiler has some startup cost. It's essentially gathering data about all the current scripts on the page. This startup cost is what's labeled as "Profiling Overhead".

That cost won't exist unless you're profiling, so it doesn't affect real users. :)

Source: I work on DevTools and added this particular event to the UI.

Rainbolt