New submission from Scott M <scott.m...@comcast.net>:
New to Python; be gentle if I've simply missed something. i'M running on
Windows XP, using a recently downloaded 2.7.1. I'm running by hitting F5 in
IDLE.
The attached .py creates 2 threads, one which updates a Tkinter label 10 times
a second forever, and one which sleeps for a second and then thrashes the CPU
for ~4 seconds, forever. I wrote this to see how Python dealt with CPU-pig
threads, and was pleased to see both threads got to run in a decently
interleaved way, even in the face of a tight loop.
But at a random point, one of the threads (which one varies) stops running. The
other continues fine. The problem manifests in less then 5 minutes (often less
than 1).
At least once, but not ever time, the thread that stopped gave a traceback:
Exception in thread Thread-1:
Traceback (most recent call last):
File "D:\Python27\lib\threading.py", line 530, in __bootstrap_inner
self.run()
File "F:\Python27\MyProjects\e.py", line 24, in run
print "evil!" #<--- point 1
File "D:\Python27\lib\idlelib\rpc.py", line 595, in __call__
value = self.sockio.remotecall(self.oid, self.name, args, kwargs)
File "D:\Python27\lib\idlelib\rpc.py", line 211, in remotecall
return self.asyncreturn(seq)
File "D:\Python27\lib\idlelib\rpc.py", line 240, in asyncreturn
response = self.getresponse(seq, wait=0.05)
File "D:\Python27\lib\idlelib\rpc.py", line 280, in getresponse
response = self._getresponse(myseq, wait)
File "D:\Python27\lib\idlelib\rpc.py", line 305, in _getresponse
cvar = self.cvars[myseq]
KeyError: 8680
BUT in some cases there wasn't a traceback (the last time there wasn't, it was
BThread that had stopped running; the label was no longer updating.)
If you comment out the print at point 2, or point 1, it seems to work fine, at
least for as long as I cared to watch it.
Also, I've noticed that if I close the app's window, that at least one thread
keeps running and writing to the Python shell console. (One generally dies
because the Tkinter label has gone away). They are both marked as daemonic;
shouldn't they stop more or less instantly?
----------
components: Interpreter Core
files: e.py
messages: 126282
nosy: PythonInTheGrass
priority: normal
severity: normal
status: open
title: thread hang, possibly related to print
type: behavior
versions: Python 2.7
Added file: http://bugs.python.org/file20409/e.py
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue10909>
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