Problem with Jobe Server

Problem with Jobe Server

by Shankar Jha -
Number of replies: 4


I have installed jobe server on my local system and installed the numpy in it but I am getting an error saying segmentation fault.

I am attaching the error screenshot below



This is my configuration setting



Has anyone run into the same problem or anyone knows how to solve this?

Any help would be really appreciated.

Regards,

In reply to Shankar Jha

Re: Problem with Jobe Server

by Richard Lobb -

numpy is rather resource hungry. You will need to raise the memory limit in the runguard sandbox on Jobe. If you're going to be using numpy a lot you'll probably want to create a new python3 prototype (editing the existing one isn't recommended) with increased limits, but for now I suggest you experiment by editing just that particular question. In the author edit form, click the Customise checkbox, then open the Advanced Customisation panel. Increase the memory limit to 500 MB as shown in the image below. The image also shows an increased setting for the process limit (numprocs) but that shouldn't be necessary unless you have a huge number of cores on your Jobe server.

Advanced customisation for numpy

Richard

In reply to Richard Lobb

Re: Problem with Jobe Server

by Padmanabhan Rajan -
Hi Richard and others,

I have been having the same problem as given in this thread for the past few days. This is my second Coderunner setup: the first one did not have this issue. Maybe the version of the operating system (ubuntu 18 i think) has something to do with it as well.
Anyway, the solution proposed by Richard above did not work for me. After some googling, I found a hack:
https://stackoverflow.com/questions/52026652/openblas-blas-thread-init-pthread-create-resource-temporarily-unavailable

Basically, we need to add the following in the code:

import os

os.environ['OPENBLAS_NUM_THREADS'] = '1'

before

import numpy as np

I added this both in the model solution on Coderunner, and the student submission as well. This hack seems to work, and I dont get the segmentation fault anymore.
It probably has to do something with the operating environment where Coderunner is installed. Hope this helps!

Regards
Padmanabhan
IIT Mandi, India
In reply to Padmanabhan Rajan

Re: Problem with Jobe Server

by Richard Lobb -

Belated thanks, Padmanabhan. Could be useful to anyone for whom increasing numprocs doesn't work (though I don't really understand why not).

Richard

In reply to Richard Lobb

Re: Problem with Jobe Server

by Richard Lobb -

I just got the same error myself, where increasing numprocs didn't work. It turned out that the task wasn't actually running out of processes or threads at all; rather, it was running out of memory while creating new worker threads. So the error message was rather a red herring. Just increasing the memory limit solved it.