Bug#737675: openblas: openmp change deadlocks python-scipy

[Julian Taylor]

On 04.02.2014 22:52, Sébastien Villemot wrote:
> Le mardi 04 février 2014 à 22:42 +0100, Julian Taylor a écrit :
> 
>> it will deadlock eating all cpu in gomp at the end.
>> This is the typical failure pattern caused by forks combined with gnu
>> openmp (see https://github.com/xianyi/OpenBLAS/issues/294)
>>
>> But the weird part is this testsuite does not fork at all, so it might
>> be a different issue.
>> It did not occur when openblas was still using pthreads.
> 
> These two paragraphs contradict each other. Is it a fork issue or not?

as I said it looks like a classical well known fork issue, but its not
forking, so I don't know yet whats going on.

> 
>> Given the problems openmp based openblas causes in the python world (see
>> the linked issue) I would prefer if the change was reverted or openmp
>> variant split into a separate alternative.
> 
> I would rather keep the libopenblas-base package with OpenMP, and create
> a new libopenblas-pthread0 package.
> 

I would prefer it the other way round as in my experience pthread works
better. But this viewpoint is of course scewed by the software I'm using.

A compromise could be to have -base single threaded and provided two
threaded alternatives documenting their issues.