Vesper: Measuring time-to-interactivity for web pages

Ravi Netravali, Vikram Nathan, James Mickens, Hari Balakrishnan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

22 Scopus citations

Abstract

Everyone agrees that web pages should load more quickly. However, a good definition for “page load time” is elusive. We argue that, for pages that care about user interaction, load times should be defined with respect to interactivity: a page is “loaded” when above-the-fold content is visible, and the associated JavaScript event handling state is functional. We define a new load time metric, called Ready Index, which explicitly captures our proposed notion of load time. Defining the metric is straightforward, but actually measuring it is not, since web developers do not explicitly annotate the JavaScript state and the DOM elements which support interactivity. To solve this problem, we introduce Vesper, a tool that rewrites a page's JavaScript and HTML to automatically discover the page's interactive state. Armed with Vesper, we compare Ready Index to prior load time metrics like Speed Index; across a variety of network conditions, prior metrics underestimate or overestimate the true load time for a page by 24%-64%. We introduce a tool that optimizes a page for Ready Index, decreasing the median time to page interactivity by 29%-32%.

Original languageEnglish (US)
Title of host publicationProceedings of the 15th USENIX Symposium on Networked Systems Design and Implementation, NSDI 2018
PublisherUSENIX Association
Pages217-231
Number of pages15
ISBN (Electronic)9781939133014
StatePublished - 2018
Externally publishedYes
Event15th USENIX Symposium on Networked Systems Design and Implementation, NSDI 2018 - Renton, United States
Duration: Apr 9 2018Apr 11 2018

Publication series

NameProceedings of the 15th USENIX Symposium on Networked Systems Design and Implementation, NSDI 2018

Conference

Conference15th USENIX Symposium on Networked Systems Design and Implementation, NSDI 2018
Country/TerritoryUnited States
CityRenton
Period4/9/184/11/18

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications
  • Control and Systems Engineering

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