CSS Performance between class and attribute selectors

Question

I'm wondering if there is a performance issue using attribute selectors instead of class selectors.

div.test {}
div[test] {}

P.S. : I'm only interested in CSS performance, not JS.

Answer 1

According to this article, class selectors are more efficient than attribute selectors.

Answer 2

According to this project there is no real performance issue.

This surprised us, since selector performance hasn't been a real concern in our day-to-day work for a while. Front-end performance is a huge deal, of course, but CSS selectors appear to contribute such a minuscule amount to the total page load time that it didn't occur to us that it might be a major concern to many people.

They have benchmarks as well. EDIT: see comment: they have benchmark ideas*, not benchmarks.

https://github.com/amcss/am-benchmarks