Asyncrhonous cuFFT batched execution

Accelerated Computing GPU-Accelerated Libraries
1

I have a 3D grid with a float3 assigned to each cell and I want to perform, for each component of the float3, a 3D FFT.

The cufft plan is as follows:

int n = 200;
 int dim[] = {n, n, n}; 
 cufftPlanMany(&cufft_plan,                                                                                                                                                             
               3, dim, /*Three dimensional FFT*/                                                                                                                                    
               dim,                                                                                                                                                                 
               /*Each FFT starts in 1+previous FFT index. FFTx in 0*/                                                                                                                           
               3, 1, //Each element separated by three others x0 y0 z0 x1 y1 z1...                                                                                                              
               dim,                                                                                                                                                                 
               3, 1,                                                                                                                                                                            
               /*Perform 3 FFTs*/                                                                                                                                                               
               CUFFT_R2C, 3);

So I am saying, do three 3D FFTs with this data.

I want the three FFTs to execute concurrently. I guess I could do this by creating three plans and assigning a stream to each one.
But I wonder, can one configure cuFFT to perform the batched calls asynchronously?

So I can just call:

cufftExecR2C(cufft_plan, (cufftReal*)in, (cufftComplex*)out);

And let cuFFT execute the three FFTs at the same time (if the device has enough resources!)

Greetings!

2

batching of calls allows cufft to use the device most effectively. It will do as much work as it can on all 3 transforms (in this example). You don’t need to do anything specific to enable this, and it is a superior approach to issuing the calls for single transforms in separate streams.

3

Thank you for your answer!
So, always choose batching over multiple plans on multiple streams whenever possible, right?

4

Yes, for the case where you are using a single GPU.

5

Got it, tx bob!