We compare four loaders, each filled with a class map:
We can see that the overhead caused by the findFile() indirection is even bigger than the difference caused by APC vs ClassMap.
LOADER DURATION RATIO CLASS_EXISTS
> CLASSMAP: ComposerSmartImmediate: 6.110430μs (1.21x) 0
> CLASSMAP: ComposerSmartImmediateReturn: 6.272978μs (1.24x) 0
> CLASSMAP: APC: 8.257363μs (1.63x) 0
> CLASSMAP: ComposerSmart: 9.140730μs (1.80x) 0
Should we care?