当我们在Spring中使用SLF4J或Log4J而不是JCL时，编译时绑定的性能优势是什么？

Question

Spring documentations states:

SLF4J is a cleaner dependency and more efficient at runtime than commons-logging because it uses compile-time bindings instead of runtime discovery of the other logging frameworks it integrates.

Allegedly there is also a performance benefit because the bindings are at compile-time not runtime.

What exactly does this compile time binding mean here? And how does it impact the performance?