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Performance and Profiling (discussion)

Discussion about Performance and Profiling.

Java dynamic dispatch

There are some serious mistakes in the last paragraph:

  • Dynamic method dispatch itself is seldom a performance problem. In languages without multiple inheritance (e.g. Java) this is usually done via one step of pointer indirection. Objects in OCaml are also dynamically dispatched. Since this is the point with polymorphism in an OO setting.

  • Dynamic method dispatch often hinders a compiler to inline function and this hits the performance.

  • In Java is a dynamic type check (aka cast) much more expensive than a dynamic method dispatch.