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[Bernhard Stegmaier <stegmaier@xxxxxxxxxxxxx>]

I did look around a bit.
Looks like OpenMP isn’t a friend of Xcode clang, because Apple has its own Grand Central Dispatch (libdispatch) implementation/library doing similar things (at first glance, didn’t look into details).
So, I guess OpenMP maybe won’t happen soon with stock toolchain or we would have to use non-stock toolchain (probably with all problems that come with that - I have seen bad things mixing compilers, etc.).

Seems to be quite easy to convert OpenMP for loop parallelisation to GCD:
<<<
    //#pragma omp parallel for
    //for( signed int i = 0; i < aPolySet.OutlineCount(); ++i )
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    dispatch_apply(aPolySet.OutlineCount(), queue, ^(size_t i)
    {
        ...
    }
    );
>>>

I just naively replaced all of the OpenMP for loops like above and now 3d-Viewer uses all cores.
On my i7-3770T rendering time decreased from about 100s to 30s.

I also did it for the ratsnest loop but didn’t notice any difference (maybe my test PCB was just to small).

I could play around a bit to put that stuff into some nice syntax maybe similar to what Microsoft has with concurrency::parallel_for_each
  https://msdn.microsoft.com/en-us/library/dd492857.aspx <https://msdn.microsoft.com/en-us/library/dd492857.aspx>
So, at least ugly #ifdef around each parallel for loop could be hidden.

Don’t get me wrong, I don’t want to add just another parallelisation library/mechanism.
And… I guess it won’t be possible to transparently cover all the OpenMP pragma stuff maybe needed inside for loop body or maybe other stuff needed for GCD (e.g. when writing to variables outside for body).

Thoughts? Would this be an option?

Oh, yes:
I did look into using STL std::async.
Doesn’t seem to be a good idea, because it usually doesn’t seem to use anything like thread pools, etc. on various platforms.
You probably don’t want to create that much threads… :) 


Regards,
Bernhard

> On 1. Mar 2018, at 08:40, Bernhard Stegmaier <stegmaier@xxxxxxxxxxxxx> wrote:
> 
> I had a quick look where OpenMP is used.
> 
> I found it somewhere in the connectivity/ratsnest code.
> I don’t know of any complaints in that area and even on my old HW I had never a bad experience.
> 
> And then, 3D-Viewer.
> 
> So, in my opinion it is basically only about 3D-Viewer… I don’t know if user experience will be that bad without OpenMP.
> IMHO it’s only the Raytracing view, which isn’t intended to be used for normal viewing stuff anyway.
> 
> If I find some time over the weekend I will also try… but I don’t think it will be worth it.
> 
> 
> Regards,
> Bernhard
> 
>> On 1. Mar 2018, at 00:50, Jeff Young <jeff@xxxxxxxxx> wrote:
>> 
>> Or rip it out and use STL?
>> 
>>> On 28 Feb 2018, at 23:38, Jon Evans <jon@xxxxxxxxxxxxx> wrote:
>>> 
>>> Hi all,
>>> 
>>> Does anyone have a working build setup for getting OpenMP-enabled KiCad out of MacOS?
>>> If so, please share how -- I tried for a bit but couldn't get it going (I'm not super familiar with the MacOS toolchain yet).
>>> 
>>> We should make sure that the 5.0 release is built with OpenMP, otherwise our Mac users are going to have a slower user experience.
>>> 
>>> -Jon
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