They gave the industry about 6 months notice to update their sites ready and most did.
Video
In this video I will explain to you some of the best tools to use for measuring page speed as well as some of the more advance things we do.
The great thing is that all of these tools are free to use.
The Tools
Web.dev
WebPageTest
Pingdom
GT Metrics
Google Analytics
Server Logs (rarely used)
Advance
Most people just measure there homepage, which is a good start, but usually the home page just ranks for the brand terms, you need to be analysing your key commercial pages, blog pages etc.
You can use tools like Batchspeed to bulk analyse 500 pages, while its not as in-depth as doing indiivdual page analysis, it does tell you the main issues, but more importantly, you can see the slow loading pages and then analyse these individually in some of the tools to find the issues.