[IPython-dev] multiprocessing from within notebook crashes kernel

Satrajit Ghosh satra at mit.edu
Wed Oct 3 16:56:47 EDT 2012


thanks min. that's exactly it.

cheers,

satra

On Wed, Oct 3, 2012 at 2:26 PM, MinRK <benjaminrk at gmail.com> wrote:

>
>
> On Wed, Oct 3, 2012 at 11:17 AM, Satrajit Ghosh <satra at mit.edu> wrote:
>
>> hi min,
>>
>> just getting back to this error. turns out that this error results from
>> an interaction between our library's logging mechanism (using python
>> logging module), the ipython kernel (happens with notebook and console but
>> not with ipython on terminal) and multiprocessing. i don't get the same
>> error running the same set of commands in the ipython terminal. i suspect
>> it has to do with how logging output is trapped and conveyed in the
>> multiprocessing context back to the browser.
>>
>
> Anything that tries to write to sys.stdout/err from a fork will definitely
> crash the process: https://github.com/ipython/ipython/issues/2438
>
>
>>
>> cheers,
>>
>> satra
>>
>>
>> On Sun, Sep 9, 2012 at 2:22 PM, MinRK <benjaminrk at gmail.com> wrote:
>>
>>> What version of pyzmq?  If it's less than 2.2.0.1, try upgrading.
>>> -MinRK
>>>
>>> On Sun, Sep 9, 2012 at 6:35 AM, Satrajit Ghosh <satra at mit.edu> wrote:
>>>
>>>> hi all,
>>>>
>>>> we are using a workflow library that internally uses multiprocessing to
>>>> distribute jobs locally. when we run this from the notebook, it crashes the
>>>> kernel.
>>>>
>>>> any thoughts as to why this might happen.
>>>>
>>>> here is the code from the library:
>>>>
>>>>
>>>> https://github.com/nipy/nipype/blob/master/nipype/pipeline/plugins/multiproc.py
>>>>
>>>> cheers,
>>>>
>>>> satra
>>>>
>>>>
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