[Bf-committers] OpenMP issues with msvc2013 builds

[Martijn Berger]

Hi Campbell,

I last compiled with intel c++ a few month's ago and without OSL / Collada.
In general it works but as with any change it will again probably expose
lots of little issues once people actually use builds intensively.

Main issue is the compiler is not free to use for windows not even for open
source projects. ( the linux toolchain is free for open source ).



On Wed, Aug 6, 2014 at 12:43 PM, Campbell Barton <ideasman42 at gmail.com>
wrote:

> 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.
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