Is the Web ready for HTTP/2 Server Push?

TL;DR

This paper evaluates the effectiveness of HTTP/2 Server Push on real-world websites, revealing that while it can improve performance with proper strategies, it often requires deep web engineering knowledge and is not universally beneficial.

Contribution

It introduces a testbed for replaying websites to study Server Push strategies and proposes a novel scheduler to improve resource interleaving, highlighting the need for better understanding of web engineering.

Findings

Server Push can improve visual progress with proper strategies

Many websites do not benefit from Server Push without careful tuning

A new scheduler can enhance resource interleaving and performance

Abstract

HTTP/2 supersedes HTTP/1.1 to tackle the performance challenges of the modern Web. A highly anticipated feature is Server Push, enabling servers to send data without explicit client requests, thus potentially saving time. Although guidelines on how to use Server Push emerged, measurements have shown that it can easily be used in a suboptimal way and hurt instead of improving performance. We thus tackle the question if the current Web can make better use of Server Push. First, we enable real-world websites to be replayed in a testbed to study the effects of different Server Push strategies. Using this, we next revisit proposed guidelines to grasp their performance impact. Finally, based on our results, we propose a novel strategy using an alternative server scheduler that enables to interleave resources. This improves the visual progress for some websites, with minor modifications to the deployment. Still, our results highlight the limits of Server Push: a deep understanding of web engineering is required to make optimal use of it, and not every site will benefit.