paulirish/speedline

first trace event can be far off from navStart

patrickhulce opened this issue · 0 comments

patrickhulce commented

discovered in GoogleChrome/lighthouse#2095

Traces can sometimes contain events that are far before navStart, even in more regular cases I've seen screenshots from the previous page linger in a trace of the new page that throws off the computation.

Two proposals with varying degrees of urgency:

  1. filter out screenshots before the user-provided timeOrigin opt (PR: #2114)
  2. consider defaulting startTs to the last occurrence of navigationStart for the root frame instead of the first event of the trace (#38)