Most recent Google AdSense often provides performance report about your website, there are some new concepts but the main seems Scorecard.
Your scorecard provides you with a summary of how well your ad settings, webpages and content are performing compared to those of other AdSense publishers. The scorecard is organized into different categories, such as revenue optimization and site health, with each category scored on a scale of one to five blue dots indicating your performance. You can further understand your performance and the steps you can take to improve it by following the suggestions and improvement tips in each category.
We got a Site heath analyzing report about PageSpeed
After click the Analyzed link, we got the following report:
We can see our scores on Desktop and Mobile, also, please note there are different suggestions, yellow color indicates optional fixing suggestion, but red color indicates you must fix it other wise related platform devices can not see your web page directly, or very slow speed.
the following is a sample about optional fixing suggestion:
Your page has 3 blocking CSS resources. This causes a delay in rendering your page.
None of the above-the-fold content on your page could be rendered without waiting for the following resources to load. Try to defer or asynchronously load blocking resources, or inline the critical portions of those resources directly in the HTML.