To help focus our attention on CPU, several new performance metrics have been defined and evangelized over the last year or three. In this post I'm going to focus on these:
Here's a figure to help visualize these metrics.
<link rel="preload" href="main.js" as="script">
The number of performance metrics is large and increases every year. It's important to understand what the different metrics represent and pick metrics that are important for your site. Our Evaluating rendering metrics post was a popular (and fun) way to compare and choose rendering metrics. Recently I created this timeline of performance metric medians from the HTTP Archive for the world's top ~1.3 million sites:
We're excited to announce the availability of the First Input Delay metric as part of LUX, SpeedCurve's RUM product.