[IPython-dev] IPython+zmq and fork()

Jason Grout jason-sage at creativetrax.com
Thu Apr 12 11:01:25 EDT 2012

On 4/12/12 9:43 AM, Volker Braun wrote:
> Sage is getting ready to upgrade to the new IPython, excuses for any email
> deluge on this list. One question that I have is whether you thought about
> fork() to quickly spawn children (this is crucial for Sage since starting up
> a new Sage process is quite slow). According to the zeromq mailinglist, you
> shouldn't fork after creating a zmq context. This is not just a theoretical
> problem, I wrote a clustering tool for my own purposes and found out the
> hard way that bad things can happen if you do.
> Will IPython always be usable without zmq?  You are not planning to
> eventually deprecate the non-zmq console client? Or maybe you have some
> awesome other solution?

Just as a point of reference, this documentation page (which seems to be 
outdated, maybe?) indicates that a single-user command line session will 
eventually use a 2-process model with zmq to communicate between the 




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