[Bf-committers] OpenMP issues with msvc2013 builds

[Sergey Sharybin]

Switching to icc wouldn't happen any time soon anyway, so afraid we'll need
to have some shorter-term solution anyway... The question only is what
exactly we'll choose.

P.S. And yeah, there's nothing more permanent as a temporary solution..


On Wed, Aug 6, 2014 at 4:48 PM, Martijn Berger <martijn.berger at gmail.com>
wrote:

> 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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> >
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-- 
With best regards, Sergey Sharybin