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Comment by CyberDildonics

16 hours ago

Reinventing data structures poorly is very common.

Heap allocation in java is something trivial happens constantly. People typically do funky stuff with memory allocation because they have to, because the GC is causing pauses.

People avoid system allocators in C++ too, they just don't have to do it because of uncontrollable pauses.

> People typically do funky stuff with memory allocation because they have to

This same dev did things like putting what he deemed as being large objects (icons) into weak references to save memory. When the references were collected, invariably they had to be reloaded.

That was not the source of memory pressure issues in the app.

I've developed a mistrust for a lot of devs "doing it because we have to" when it comes to performance tweaks. It's not a never thing that a buffer is the right thing to do, but it's not been something I had to reach for to solve GC pressure issues. Often times, far more simple solutions like pulling an allocation out of the middle of a loop, or switching from boxed types to primatives, was all that was needed to relieve memory pressure.

The closest I've come to it is replacing code which would do an expensive and allocation heavy calculation with a field that caches the result of that calculation on the first call.

  • I'm not sure why you're rationale for how to deal with garbage collected memory is based on a guy that didn't know standard data structures and your own gut feelings.

    Any program that cares about performance is going to focus on minimizing memory allocation first. The difference between a GCed language like java is that the problems manifest as gc pauses that may or may not be predictable. In a language like C++ you can skip the pauses and worry about the overall throughput.

    • Right? "I had this one contingent experience and I've built my entire world view and set of practices around it."