Learning HTTP/2

Chapter 6. HTTP/2 Performance

One of the goals of HTTP/2 was improved performance. For some, this is the only reason to switch over. Though h2 will generally be faster than HTTP/1.1 for web page delivery, it is not always the case. Understanding the conditions that affect h2’s performance is an important part of tuning your site and understanding end users’ experiences. Many variables need to be taken into consideration when measuring the performance of h2, and this assesment goes well beyond classifications of “slower” or “faster.” This chapter will explore the most important factors that contribute to real-world HTTP/2 performance.

Client Implementations

HTTP/2 is a young protocol and as is often the case, implementations, though spec compliant, can vary in subtle but important ways. For example, browsers like Chrome, Firefox, Safari, and Microsoft Edge all have different quirks that may affect a user’s experience on your site. The performance of the same website using different clients from within the same network connection can show considerable differences in page load times. Understanding these differences can be a critical part of tuning your site for the largest possible audience.

Akamai’s Foundry Team performed a study of HTTP/1.1 versus HTTP/2 performance with a goal of understanding how different browsers compare. It involved looking at billions of Real User Monitoring (RUM) measurements from real devices under real network conditions. The results showed differences ...