Application level threading of 2D DFT

[packj]

I am using IPP 7.0 to write some code that will perform a series of 2D image filtering operations on images of various sizes (mostly 128 by 128). I have two versions of the code: one that leaves the threading up to IPP (internal to the DFT call, for example), and another in which I handle the threading myself at the application level.I have found that the IPP threading does notprovide any significant speedupfor the small sizedDFT operations (like 128 by 128) and so I really want to use application level threading. When Ido this, however,the final images are not correct. If I run the two threads serially, things work fine, but when I run them in parallel the result is wrong. I suspect that I need to provide more information than what I have provided, but I'm not sure what ype of information would be most useful. The IPP functions I am using are as follows:

ippiDFTFwd_RToPack_32f_C1IR
ippsRealToCplx_32f
ippiCplxExtendToPack_32fc32f_C1R
ippiMulPack_32f_C1IR
ippiDFTInv_PackToR_32f_C1IR

I tried simplifying the code somewhat by just doing the DFT, then zeroing out the DC component and then doing the InvDFT. I still got the same result (twothreads running in parallel give the wrong answer, while two threads running serially give the correct answer). In this simple case, the only IPP functions I use are as follows:

ippiDFTFwd_RToPack_32f_C1IR
ippiDFTInv_PackToR_32f_C1IR

Please let me know what other information I can provide that might help in diagnosing this.

Thanks for your help!

[packj]

Nevermind... it was my error. I think I have it working correctly now.

[Rama_Krishna]

Hi,
How to create native thread in application using IPP.could you please share example which you have done for 2D DFT

Regards,
rama

[timintel]

Quoting Rama Krishna

Hi,
How to create native thread in application using IPP.could you please share example which you have done for 2D DFT

Regards,
rama

I don't think your question is clear. If it is about IPP, there is a forum specifically for that. If it is about Windows or linux threading, the forum for the compiler you intend to use might be appropriate.

[Gennady_F_Intel]

Please try to link IPP with the non-threaded version and check how it will work.

--Gennady