Evaluating overhead of performance.mark()

A few conversations have circled around user-side structural profiling. For context, see React PR #7549: Show React events in the timeline when ReactPerf is active

One particular concern is the measurement overhead. This gist has a benchmarking script (measure.js) for evaluating overhead and initial results.

Results: performance.mark()

Runs about 0.65µs per mark() call. Naturally, that's ~= an overhead of 1ms for 1500 mark()s.

Results: performance.measure()

Calls to measure() are not significantly more expensive than calls to mark(). They appears to be ~30% more expensive than a mark(), but still only clocking in at ~0.85µs per measure() call.

(If benchmarking, be sure to run timeline against your benchmark; I've seen large DOM GC's when calling measure >50,000 times a second. :)

Results: console.time()

console.time is much more expensive at ~11.5 µs/call (thats ~18x slower than perf.mark()). Therefore, it's not recommended. Also it spams your console, so it's inconvenient to use for high-volume work.