Inheritance was invented as a performance hack (2021)
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Re: Inheritance was invented as a performance hack (2021)
#2Huh, I was always told that inheritance hurt performance as it requires additional address lookups. Thats why many game engines are moving away from it.
I guess it could simplify the GC but modern garbage collectors have come a long way.
Re: Inheritance was invented as a performance hack (2021)
#3Huh, I was always told that inheritance hurt performance as it requires additional address lookups. Thats why many game engines are moving away from it. I guess it could simplify the GC but modern garbage collectors have come a long way.
As I understand it, back when Simula and LISP were invented it was generally the case that loads and stores took 1 cycle and there were no CPU caches. These pointer-chasing languages and techniques really weren't technically bad for the computers of the time - it's just that we have a larger relative penalty for randomly accessing our Random Access Memory these days so locallity is important (hence data-oriented design, ECS, etc).
I am kind of amused they _removed_ first-class functions though!
Re: Inheritance was invented as a performance hack (2021)
#4Favorite part of this is that I had no idea if this article was going to be about biology, code or money. I love a good surprise
Re: Inheritance was invented as a performance hack (2021)
#5Huh, I was always told that inheritance hurt performance as it requires additional address lookups. Thats why many game engines are moving away from it. I guess it could simplify the GC but modern garbage collectors have come a long way.
Simple inheritance makes the class hierarchy complicated through issues like the diamond inheritance problem, which C++ resolves in typical C++ fashion: attempt to satisfy everybody, actually satisfy nobody.
The designers of StarCraft ran into the pitfalls of designing a sensible inheritance hierarchy, as described here (C-f "Game engine architecture"): https://www.codeofhonor.com/blog/tough-times-on-the-road-to-...
Re: Inheritance was invented as a performance hack (2021)
#6Huh, I was always told that inheritance hurt performance as it requires additional address lookups. Thats why many game engines are moving away from it. I guess it could simplify the GC but modern garbage collectors have come a long way.
Dynamic invocation, not strict inheritance is the issue here. Simply getting functions and fields from a superclass costs nothing if at each callsite the compiler knows enough to say where it is from.
Re: Inheritance was invented as a performance hack (2021)
#7Huh, I was always told that inheritance hurt performance as it requires additional address lookups. Thats why many game engines are moving away from it. I guess it could simplify the GC but modern garbage collectors have come a long way.
Simple inheritance makes the class hierarchy complicated through issues like the diamond inheritance problem, which C++ resolves in typical C++ fashion: attempt to satisfy everybody, actually satisfy nobody. The designers of StarCraft ran into the pitfalls of designing a sensible inheritance hierarchy, as described here (C-f "Game engine architecture"): https://www.codeofhonor.com/blog/tough-times-on-the-road-to-...
really amazing read thank you.
Re: Inheritance was invented as a performance hack (2021)
#8Favorite part of this is that I had no idea if this article was going to be about biology, code or money. I love a good surprise
My first assumption was something like ACL lists (though this could be for something like NTFS, or directory permissions) or even Firewall rules but I guess we all bring our background to assumptions
Re: Inheritance was invented as a performance hack (2021)
#9Huh, I was always told that inheritance hurt performance as it requires additional address lookups. Thats why many game engines are moving away from it. I guess it could simplify the GC but modern garbage collectors have come a long way.
Nah. Classic C++/Java style inheritance with vtable dispatch is very fast. Generally no slower than a C-style function call, and actually sometimes faster depending on how the C code is linked, characteristics of the CPU, etc.
Re: Inheritance was invented as a performance hack (2021)
#10I'm not sold the evidence is there to show inheritance is a good idea - it basically says that constructors, data storage and interfaces need to be intertwined. That isn't a very powerful abstraction, because they don't need to be and there isn't an obvious advantage from doing so over picking up the concepts separately as required. And inheritance naturally suggests grouping interfaces into a tree in the way that seems of little value because in practice a tree probably doesn't represent the fundamental truth of things. Weird edge cases like HTTP over non-TCP protocols or rendering without screens start throwing spanners into a tree of assumptions that never needed to be made and pull the truth-in-code away from the truth-in-world.
All that makes a lot of sense if it was introduced as a performance hack rather than a thoughtfully designed concept.