[Insight-users] FFTW thread safety

[Cory Quammen]

Simon,

I've merged a patch based on your suggestion into ITK master.

http://www.itk.org/gitweb?p=ITK.git;a=commit;h=a0661da4252fcdd638c6415c89cd2f26edd9f553

Thanks for contributing to ITK!

Cory

On Wed, Nov 14, 2012 at 12:19 PM, Simon Rit
<simon.rit at creatis.insa-lyon.fr> wrote:
> You're right, this is now useless in ITK4. In the previous version
> taken from the insight journal
> (https://github.com/SimonRit/RTK/blob/master/utilities/itkfftw/itkFFTWCommon.h)
> the instantiation was not protected and, therefore, it was
> thread-unsafe. Thanks for the correction,
> Simon
>
> On Wed, Nov 14, 2012 at 6:11 PM, Cory Quammen <cquammen at cs.unc.edu> wrote:
>> Also, I meant to ask you why adding a Lock/Unlock pair in
>> BeforeThreadedGenerateData was necessary. The lock appears to be
>> initialized at instantiation, so perhaps it isn't necessary for you to
>> do that?
>>
>> Thanks,
>> Cory
>>
>> On Wed, Nov 14, 2012 at 12:09 PM, Cory Quammen <cquammen at cs.unc.edu> wrote:
>>> Simon,
>>>
>>> I posted a patch to gerrit. You can review it here:
>>>
>>> http://review.source.kitware.com/#/c/8506/
>>>
>>> Thanks,
>>> Cory
>>>
>>> On Wed, Nov 14, 2012 at 9:53 AM, Cory Quammen <cquammen at cs.unc.edu> wrote:
>>>> Simon,
>>>>
>>>> Thank you for the patch. I will post a patch based on your patch to
>>>> gerrit when I have a moment today, unless someone beats me to it.
>>>>
>>>> Cory
>>>>
>>>> On Wed, Nov 14, 2012 at 9:48 AM, Simon Rit
>>>> <simon.rit at creatis.insa-lyon.fr> wrote:
>>>>> Hi,
>>>>> I have experienced problems with FFTW in ITK 4. I am doing many
>>>>> parallel FFT filters, each parallel thread having the piece of the
>>>>> image defined by ThreadedGenerateData. This is a filter part of
>>>>> www.openrtk.org which code is here:
>>>>> https://github.com/SimonRit/RTK/blob/master/code/rtkFFTRampImageFilter.txx
>>>>>
>>>>> I have originally done that with the code of Gaëtan Lehmann
>>>>> (http://www.insight-journal.org/browse/publication/717) but I had to
>>>>> fix it then for thread safety. I have now moved to ITK4 but I think
>>>>> that the thread safety issue is still here since I have random
>>>>> crashes. The problem is that the destroy functions are not protected
>>>>> by the mutex although they are not thread safe
>>>>> (http://www.fftw.org/doc/Thread-safety.html). So a lock / unlock must
>>>>> be added around it in itkFFTWCommon.h.
>>>>> The patch is below, let me know what you think.
>>>>> Simon
>>>>>
>>>>> PS: It is also worth of note that I have added a Lock/Unlock in the
>>>>> BeforeThreadedGenerateData function of my filter to ensure that the
>>>>> mutex is initialized.
>>>>>
>>>>> The patch:
>>>>>
>>>>> @@ -351,7 +350,9 @@ public:
>>>>>    }
>>>>>    static void DestroyPlan(PlanType p)
>>>>>    {
>>>>> +    FFTWGlobalConfiguration::Lock();
>>>>>      fftwf_destroy_plan(p);
>>>>> +    FFTWGlobalConfiguration::Unlock();
>>>>>    }
>>>>>  };
>>>>>
>>>>> @@ -653,7 +654,9 @@ public:
>>>>>    }
>>>>>    static void DestroyPlan(PlanType p)
>>>>>    {
>>>>> +    FFTWGlobalConfiguration::Lock();
>>>>>      fftw_destroy_plan(p);
>>>>> +    FFTWGlobalConfiguration::Unlock();
>>>>>    }
>>>>>  };
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>>>>
>>>>
>>>>
>>>> --
>>>> Cory Quammen
>>>> Research Associate
>>>> Department of Computer Science
>>>> The University of North Carolina at Chapel Hill
>>>
>>>
>>>
>>> --
>>> Cory Quammen
>>> Research Associate
>>> Department of Computer Science
>>> The University of North Carolina at Chapel Hill
>>
>>
>>
>> --
>> Cory Quammen
>> Research Associate
>> Department of Computer Science
>> The University of North Carolina at Chapel Hill
>> _____________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Kitware offers ITK Training Courses, for more information visit:
>> http://www.kitware.com/products/protraining.php
>>
>> Please keep messages on-topic and check the ITK FAQ at:
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-- 
Cory Quammen
Research Associate
Department of Computer Science
The University of North Carolina at Chapel Hill