4 ms·

"""Does it work? Yes it's better: Sequential 23.5 seconds. Threaded 24.0 seconds.""" How is that better? It is an improvement over earlier versions of Python.

• jnoller 17y ago
  An improvement over the old implementation is better. "Fixed and Perfect" would be free-threading, where it would be twice as fast with threads. I'll take incremental, concrete improvements anytime.
• Luyt 17y ago
  If you really want to speed up your program, you have to parallelize and distribute the workload over multiple cores. Python has a module in the standard library for this, it's called 'multiprocessing'. See http://docs.python.org/library/multiprocessing.html http://docs.python.org/library/multiprocessing.html
  • rbanffy 17y ago
    It won't help if you have to do stuff over a single shared data structure.
    • st3fan 17y ago
      Well you can of course. It is just a pain to do it.
      • rbanffy 17y ago
        That's a good point. I rarely had to do it and, when I could, I opted to distribute the data. Still, Python needs better threading.
• mitchellh 17y ago
  If you look at the code he used to test this, its completely CPU-bound, meaning that it requires the GIL to run. And since the GIL is, well, a "GIL," that means that only one can run at any single time. Therefore, the expected behavior of running these two threads would be to have identical runtimes. That would be the "perfect" case with a GIL. So with this "better" GIL its actually near-perfect in this _simple_ case. (Like the presenter said, there needs to be more tests to study the behavior under heavier tasks) What you're describing, with the threaded being "twice as fast" assumes that the threads will allow two python-instruction-bound tasks to run concurrently, which would require having no GIL.
• whatusername 17y ago
  From Slide 7: Sequential (Single Core) : 24.6s Threaded (Dual Core) : 45.5s Threaded (With a CPU core diabled) : 38.0s 23.5 / 24.0 is an improvement to both tests - and a significant improvement to the Threaded one.