  Modern web pages have complex structures comprised of up to hundreds of
different resources, such as scripts and images. Server push is an HTTP/2
feature enabling servers to preemptively send resources to clients before they
realize they need them to render a page. The objective is to reduce the amount
of time the browser has to wait for data to be transferred, and consequently
total page load time. Our goal in this work is to quantify how much server push
can actually reduce web page load times. We approach the problem from both
theoretical and experimental perspectives. We start by deriving an upper bound
for the load time reduction afforded by server push. Then we proceed to
actually evaluate an idealized push implementation on the Alexa Top 100 global
sites, against a non-push HTTP/2 baseline. Our results show a linear
relationship between latency and the benefit of server push. Moreover, pages
with taller dependency trees tend to benefit the most from it.
