first of all, thanks a lot for your quick response.
On Thursday 06 December 2007, Jim Fulton wrote:
> - You should avoid runaway processes. :) I'm actually quite serious.
Yes, we are trying hard. :-)
We are currently using lovely.remotetask to export those calls even to a
different server, where we run the code in forked subprocesses.
After having played for a day with this problem, I came to the following
conclusion: Python assumes that all used C-libraries are wrapped in a way
that they are non-blocking and cannot lock up. When forking, you better know
what you are doing.
Based on your comment, I think you agree. :-)
> - You can run multiple processes and monitor their progress -- killing
> processes that are stuck.
I think this is a really good idea that requires little software and not much
> zc.z3monitor provides some output that makes this pretty straightforward.
Wow, zc.z3monitor -- and zc.ngi which I looked at too -- are very cool. How
useful! I have been following the checkins and had an idea of what it was
about, but it is definitely cooler than I thought. :-)
However, some code calls a blocking operation, zc.z3monitor will be locked up
as well. I guess then I only have to check whether I get connectivity or
> - It might be interesting to see if Java or .Net give better control
> over threads. If they do, then this might make Zope ports to Jython
> or IronPython more interesting. (People who get upset by the Python
> GIL should already find these platforms interesting.)
Java has a lot more control over threads, but I still have found complaints
that they left out some features for portability reasons. I could not
immediately find an answer on whether blocking, run-away C-calls are handled
correctly. I talked to Roy Mathew, a once at a time Java guru, and he said
that Java has a time-limit it gives each thread for doing some work. (I am
not supposed to quote him on that. ;-) So if that is true, then Java does not
have the problem.
Roy did mention, though, that debugging locked threads in Java is a common
skill after you reached a certain level of Java Zen.
I looked yesterday quiet a bit at Win32 threads. That part of the Win32 kernel
seems pretty well thought out and from what I can tell you can have quiet a
bit of control over the threads. Again, I am not sure how hanging threads are
BTW, there is a nice article on Python threads here (probably nothing new for
CBU Physics & Chemistry (B.S.) / Tufts Physics (Ph.D. student)
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