design rationale

[Norman Goldstein]

I very much appreciate the great description of how to use log4cxx. My 
question is about a design choice that affects performance (paragraph 2 
in https://logging.apache.org/log4cxx/latest_stable/usage.html ).  A 
hierarchical approach for logging levels makes sense. However, each 
run-time check of the level involves a walk of the logger hierarchy.  
Why not do this walk when assigning levels, so that the walk does not 
need to be done at each call to log i.e. each logger stores its logging 
level, directly?