Yade

Bug #1304878
Comment #7

Comment 7 for bug 1304878

Revision history for this message

Anton Gladky (gladky-anton) wrote on 2014-04-29: Re: [Bug 1304878] Re: Openblas breaks openmp

Bruno, I was trying to build Yade on 12.04 against
atlas instead of OpenBlas and got problem. It seems
yade-batch is not working in this case. Not sure yet why.

Anyway, I think 12.04 is relatively old, so we should not
spend too much efforts on this problem.

Anton

2014-04-09 14:31 GMT+02:00 Bruno Chareyre <email address hidden>:
> So a) is a lot better.
> I can update the "compile" part of the doc to explain how to compile with openblas+openmp on 12.04.
>
> --
> You received this bug notification because you are subscribed to Yade.
> https://bugs.launchpad.net/bugs/1304878
>
> Title:
> Openblas breaks openmp
>
> Status in Yet Another Dynamic Engine:
> New
>
> Bug description:
> Linking libopenblas as it is in ubuntu 12.04 disable multithread tasks (known issue with other applications to).
> Yade -jN run the parallel tasks in a sequential way, and therefore it actually slows down for increasing N due to overheads, as noticed by [1].
> The bug affects yade-daily and every build that links vs. openblas
>
> There is a simple fix for compiled versions:
> - uninstall openblas
> - git clone git://github.com/xianyi/OpenBLAS
> - edit Makefile.rule to enable openmp at line 44 in (https://github.com/xianyi/OpenBLAS/blob/develop/Makefile.rule#L43):
> # If you're going to use this library with OpenMP, please comment it in.
> # USE_OPENMP = 1 (the problem with debian/openblas is, obviously, that it is built with USE_OPENMP = 0)
> - make PREFIX=/usr/lib
> - sudo make install
> - run yade (no need to recompile)
>
> This fix should also work for prebuilt yadedaily. The only problem is
> it has openblas as a dependency, so basically the first step above
> needs to also uninstall yadedaily (you could hack it somehow, of
> course...)
>
> I'm not sure how to best fix yadedaily. I noticed openblas-omp packages available for Fedora and others, but not for debian.
> One option is to replace libopenblas dependency by libatlas (it will also eliminate the problems with scipy). The PFV code will be suboptimal and non-parallel, but people seeking performance can always recompile with openblas.
>
> What do you think Anton?
>
> [1] https://answers.launchpad.net/yade/+question/246489
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/yade/+bug/1304878/+subscriptions

Bruno, I was trying to build Yade on 12.04 against
atlas instead of OpenBlas and got problem. It seems
yade-batch is not working in this case. Not sure yet why.

Anyway, I think 12.04 is relatively old, so we should not
spend too much efforts on this problem.

Anton

2014-04-09 14:31 GMT+02:00 Bruno Chareyre <1304878@bugs.launchpad.net>:
> So a) is a lot better.
> I can update the "compile" part of the doc to explain how to compile with openblas+openmp on 12.04.
>
> --
> You received this bug notification because you are subscribed to Yade.
> https://bugs.launchpad.net/bugs/1304878
>
> Title:
>   Openblas breaks openmp
>
> Status in Yet Another Dynamic Engine:
>   New
>
> Bug description:
>   Linking libopenblas as it is in ubuntu 12.04 disable multithread tasks (known issue with other applications to).
>   Yade -jN run the parallel tasks in a sequential way, and therefore it actually slows down for increasing N due to overheads, as noticed by [1].
>   The bug affects yade-daily and every build that links vs. openblas
>
>   There is a simple fix for compiled versions:
>   - uninstall openblas
>   - git clone git://github.com/xianyi/OpenBLAS
>   - edit Makefile.rule to enable openmp at line 44 in  (https://github.com/xianyi/OpenBLAS/blob/develop/Makefile.rule#L43):
>   # If you're going to use this library with OpenMP, please comment it in.
>   # USE_OPENMP = 1 (the problem with debian/openblas is, obviously, that it is built with USE_OPENMP = 0)
>   - make PREFIX=/usr/lib
>   -  sudo make install
>   - run yade (no need to recompile)
>
>   This fix should also work for prebuilt yadedaily. The only problem is
>   it has openblas as a dependency, so basically the first step above
>   needs to also uninstall yadedaily (you could hack it somehow, of
>   course...)
>
>   I'm not sure how to best fix yadedaily. I noticed openblas-omp packages available for Fedora and others, but not for debian.
>   One option is to replace libopenblas dependency by libatlas (it will also eliminate the problems with scipy). The PFV code will be suboptimal and non-parallel, but people seeking performance can always recompile with openblas.
>
>   What do you think Anton?
>
>   [1] https://answers.launchpad.net/yade/+question/246489
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/yade/+bug/1304878/+subscriptions