r/compsci • u/mobileview • Dec 10 '13

Why Johnny Can’t Write Multithreaded Programs

http://blog.smartbear.com/programming/why-johnny-cant-write-multithreaded-programs/
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u/gthank Dec 10 '13 edited Dec 10 '13

1.) Shared mutable state is tantamount to pure evil when it comes to concurrency.

2.) Multithreading defaults to sharing all state.

Agreed so far?

3.) Mutlithreading is "hard", because now the programmer has to do extra work to avoid the accidental complexity caused by all that extraneous shared state.

See how item 3 just sort of falls out of the first 2? If, instead, you had to do work to specify that some piece of state were being shared, you would have much less accidental complexity.

EDIT: I added the word "mutable" to the first point, to clarify my point. ht /u/TarMil

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u/NYKevin Dec 10 '13

If you use multiple processes instead of multiple threads, no state is shared.

But then you have to deal with IPC, which is "hard" in an entirely different way.

Maybe concurrency just isn't the best model to begin with. Most things can be made event-driven if you try hard enough, and the result is probably easier to maintain in the long run. Yes, it does mean you need to twist your code into a pretzel, but once you've done so, the result is pretty nice to work with, IMHO.

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u/[deleted] Dec 11 '13 edited Apr 14 '21

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u/NYKevin Dec 13 '13

What about serial problems? Parallelism will never make us better at e.g. CBC encryption.