Doing some performance tests with Gerhard, we notice renderers like the one used for h:outputText does a lot of calls to getAttributes().get().
The problem is most of this calls just return null, wasting time and resources. For example, usually h:outputText uses value, style and styleClass. Think about the most basic use case where you need to show some data with just h:dataTable and h:outputText. Per each h:outputText, 6 calls to getAttributes().get() for passthrough attributes, most of them completely unnecessary. The same is true for other components.
We can reduce the number of calls if we have something that keep track of the properties already set. Obviously this will be a myfaces internal, but I think it is worth to do it at least for the most used components like h:outputText, h:outputLabel, h:outputFormat, h:outputScript and h:outputStylesheet. Note do this can make renderers harder to maintain, because some extra code should be added.
We already have some interfaces in javax.faces.component.html package like
The idea could be focus only on these set of properties, and let the others as is.
Long time ago, when I reviewed trinidad code for implement MyFaces Core Partial State Saving, I notice the class org.apache.myfaces.trinidad.bean.PropertyKey has an algorithm that assign a number to each property. Maybe we can assign a number to each property and store a flag on attribute map when it is set, and then retrieve this value from the renderer and only check the ones that needs to be rendered.