kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxx>]

Ughh!  Thank you Apple.  I'm not opposed to this idea if OpenMP isn't a
viable option on macos.  I would like to see our macos port be on par
with linux and windows ports.

Wayne

On 3/1/2018 8:20 AM, Bernhard Stegmaier wrote:
> 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
> 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
>> <mailto: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
>>> <mailto:jeff@xxxxxxxxx>> wrote:
>>>
>>> Or rip it out and use STL?
>>>
>>>> On 28 Feb 2018, at 23:38, Jon Evans <jon@xxxxxxxxxxxxx
>>>> <mailto: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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> 
> 
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