[Python-Dev] Pythonic concurrency (original) (raw)

Robert Brewer fumanchu at amor.org
Tue Oct 11 16:46:40 CEST 2005

Steve Holden wrote:

The nice thing about Python threads (or rather threading.threads) is that since each thread is an instance it's relatively easy to ensure that a thread restricts itself to manipulating thread-local resources (i.e. instance members).

This makes it possible to write algorithms parameterized for the number of "worker threads" where the workers are taking their tasks off a Queue with entries generated by a single producer thread. With care, multiple producers can be used. More complex inter-thread communications are problematic, and arbitrary access to foreign-thread state is a nightmare (although the position has been somewhat alleviated by the introduction of threading.local).

"Somewhat alleviated" and somewhat worsened. I've had half a dozen conversations in the last year about sharing data between threads; in every case, I've had to work quite hard to convince the other person that threading.local is not magic pixie thread dust. Each time, they had come to the conclusion that if they had a global variable, they could just stick a reference to it into a threading.local object and instantly have safe, concurrent access to it.

Robert Brewer System Architect Amor Ministries fumanchu at amor.org -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mail.python.org/pipermail/python-dev/attachments/20051011/39c9073f/attachment.html

More information about the Python-Dev mailing list