[Bf-committers] OpenMP issues with msvc2013 builds

[Campbell Barton]

On Wed, Aug 6, 2014 at 6:23 PM, Sergey Sharybin <sergey.vfx at gmail.com> wrote:
> Hi,
>
> We've spent quite a while trying to solve the upcoming stream of reports
> about high CPU usage with builds made with msvs2013 in certain situations.
> Root of the issue goes to the change made to OMP inplementation back to
> msvc2010 days -- they've forced threads to spin for a while after they did
> a work. This is a know issue in the library and nobody actually gonna to
> fix it [1].
>
> There's one woekaround to solve the issue which is to set OMP_WAIT_POLICY
> environment variable to PASSIVE. Unfortunately, since openmp is a dynamic
> library and can't be linked statically at all we can't modify environment
> variables from within blender using putenv(), this is to be done
> externally, before blender.exe starts.
>
> Here's the list of possible solutions:
>
> - Declare msvc full of crap, switch to intel compilers

Did anyone try Intel-c/c++ on Windows?

A while back I got Blender building on Linux with Intel's compiler, it
needed a few tweaks in CMake but wasn't really a big deal to get
running.