Thank you, Aaron, for your interest on the topic.

My main previous proposal still stands: remove bundled OpenMP submodule and
use OpenMP provided by the environment [1]. This might lead to performance
degradation in some cases where an old OpenMP library is used or thread
affinity wasn't set properly. But that would be a problem of the
environment, not MXNet.

I described some alternative solutions in [1] as part of this [2] thread.
Tricking the linker with symlinks in both cases should allow to avoid
multiple OpenMP implementations linked simultaneously to MXNet. Windows
questions would be still open.

Best
Anton

[1] https://github.com/apache/incubator-mxnet/pull/12160
[2]
https://lists.apache.org/thread.html/007d8db15a1782e1b20896a4050b62710d4ff0908c67b94af7cb0f8b@%3Cdev.mxnet.apache.org%3E
[3]
https://lists.apache.org/thread.html/4827f0f742b6e7e070da350ea81226d059401527f3072ce8b33c1fdf@%3Cdev.mxnet.apache.org%3E


вт, 12 февр. 2019 г. в 16:39, Aaron Markham <aaron.s.mark...@gmail.com>:

> This is really great research. I've often wondered what the difference
> really is, and why it has to be so complicated. It seems the answer is
> there isn't much difference and it shouldn't be as complex.
> As for your next steps, would you propose that cmake be brought up to
> parity? It seems strange that it causes slowness and if so, it shouldn't be
> recommended for now.
> Also, testing for windows compliers might be quite important as install
> stats suggest a significant portion of windows users. Wouldn't this nudge
> the decision of what to use as a rule going forward?
> I ran into this submodule openmp issue on windows myself. How does that get
> fixed? Do we have to repackage all of the submodules to make sure they use
> the recommended implementation or they use what the system expects?
>
> Cheers,
> Aaron
>
> On Tue, Feb 12, 2019, 04:37 Anton Chernov <mecher...@gmail.com> wrote:
>
> > Dear MXNet community,
> >
> > Due to multiple problems related to OpenMP and stale proposed change [1]
> we
> > have been working on gathering performance data on the impact of using
> > different OpenMP implementations with MXNet (great thanks to Stanislav
> > Tsukrov for the hard work). The results can be found here [2].
> >
> > As a short summary of the investigation: The difference between different
> > compilers is insignificant. Native OpenMP implementations (more or less
> > recent) perform equally (<5% difference). See more details in the
> document.
> >
> > Please review the document and share your thoughts on the topic.
> >
> > Thanks!
> >
> > Best
> > Anton
> >
> > [1]
> >
> >
> https://lists.apache.org/thread.html/4827f0f742b6e7e070da350ea81226d059401527f3072ce8b33c1fdf@
> > <dev.mxnet.apache.org>
> > [2] https://cwiki.apache.org/confluence/x/2wclBg
> >
>

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