Instead of sharing the code at runtime, i.e. what an OS does. You could easily share code at compile time, i.e. statically link a library.
Because of sharable code, "implementing * in application" should always be at-least as performant as the best generic implementation (i.e. the implementation you find in a general purpose OS). However, when appropriate, customizing the implementation for the application would allow it to become even more performant.
Instead of sharing the code at runtime, i.e. what an OS does. You could easily share code at compile time, i.e. statically link a library.
Because of sharable code, "implementing * in application" should always be at-least as performant as the best generic implementation (i.e. the implementation you find in a general purpose OS). However, when appropriate, customizing the implementation for the application would allow it to become even more performant.