| Speaking to some of the Google developers and the head of mobile web performance - not even Google use their own tool as a measure / benchmark for performance. PageSpeed Insights is both broken and convoluted at best. - No support for HTTP/2
-- This means that if you follow all the "right" approaches for performance with HTTP/2, you'll be slapped with a terrible PageSpeed score due to it not taking into account the effect of multi plexing connections.
- Has constant bugs around determining the flow of assets on the page and thinks that assets at the bottom become render blocking when they do not Google tend to use a combination of their own tooling + WebPageTest.org (which is also theirs) to test performance issues. This tool is mainly geared at the non-developer type, but it's unfortunately misleading and just wrong. It doesn't measure speed, it measures performance methodologies and whether they have been implemented or not (and old ones at that). The more important metrics are time to paint, time to domcontentready. Using WebPageTest will get you what you want. I find it pretty offensive and misleading that Google is using such a tool and promoting it to users, because frankly it misses the entire point of performance. Things like this:
"Eliminate render-blocking JavaScript and CSS in above-the-fold content" when you're running an H/2 site with an appcache and pushing assets is just downright wrong. It's sad that there's a general miscommunication within the company about performance. Ilya Gregorik and co say one thing, and the rest say another. |