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Comment by nicolaslem | Hacker News Reader

> Sadly, that's not practically possible.

Why? With cpython there are plenty of cases where parallelism is possible with threads because the GIL is released (for instance most IO operations and many C based number crunching operations), making threads and locks useful.

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Yes, but it's very easy to hit a number crunching operation that locks the GIL.

So technically if you wrote most of your number-crunching code as a C module for python, then you could use threads...

Can't you see a problem here?

No you can still use pure Python, and use multiple threads, and get concurrency just fine. The global lock doesn't stop you doing that! C extensions being able to release the lock is just a bonus on top.

If you don't want to use C (I don't blame you if you don't) you could use Cython or Numba. And certainly in my number crunching code the amount of code that actually crunches numbers, and thus could really benefit from being written in a GIL releasing way, is really quite small.

Lots of problems are merely I/O related, which can be solved just fine with Python threads. As for number crunching (let's assume that means CPU intensive tasks), you can always still resort to multiprocessing (which can also be combined with multithreading, I fail to see why such paradigms cannot be combined).

Well, io-related problems can be solved even better by using gevent.

The io-related problems I had with paramiko, on the other hand - last time I checked could neither be solved with threads or gevent.

So that’s a weak point to be made anyway.

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