SPDY is increasingly being used as an enhancement to HTTP/1.1. Unfortunately, the performance of SPDY is not well understood. Both SPDY and HTTP performance depend on many factors external to the protocols themselves, including network parameters, TCP settings, and Web page characteristics. Any of these factors can have a large impact on performance, and to understand their interplay it is necessary to sweep a large portion of the parameter space.
By building on top of WProf, we present what we believe to be the most in-depth study of page load time under SPDY as of early 2014. We isolate the different factors that affect PLT with reproducible experiments that progress from simple but unrealistic transfers to full page loads. By looking at results across this progress, we can systematically isolate the impact of the contributing factors and identify when SPDY helps significantly and when it performs poorly compared to HTTP.
The following pages provide more details.