waterfall chart showing gaps between metric time


We notice a gap between ‘msfirstpaint’ and ‘DOMcontentloaded’ time in the waterfall chart for our test runs, please can someone through some light why we see this gap? (screen attached)

They are different metrics, is there a reason you wouldn’t expect a gap? msFirstPaint is when the browser reports that it first painted something to the screen. DOMContentLoaded is the time when the main HTML parser has finished parsing the HTML, including executing any blocking scripts.