Mixing cublas and rustacuda ?

[zeroexcuses]

Can we please have sample code that

1. allocates some memory

2. calls A = B * C

3. calls some kernel on A

4. calls sgemm D = E * A

? I have some tensor code that runs great in CPU mode, but fails in GPU mode (so the algorithm si correct). All CPU vs GPU unit tests pass -- so it seems I am running into a synchronization issue.

I am using stream.synchronize on after all kernel calls -- so it seems the remaining culprit is that kernels on streamA while cublas is on streamB .. and it's not clear to me how to synchronize the two.

[rusch95]

Could you post a code snippet showing off this failure? I can hack on that.

On Mon, Jan 21, 2019 at 4:52 PM zeroexcuses notifications@github.com wrote:

Can we please have sample code that

1.

allocates some memory 2.

calls A = B * C 3.

calls some kernel on A 4.

calls sgemm D = E * A

? I have some tensor code that runs great in CPU mode, but fails in GPU mode (so the algorithm si correct). All CPU vs GPU unit tests pass -- so it seems I am running into a synchronization issue.

I am using stream.synchronize on after all kernel calls -- so it seems the remaining culprit is that kernels on streamA while cublas is on streamB .. and it's not clear to me how to synchronize the two.

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[zeroexcuses]

I think I got it working via the following changes:

1. I made Stream's 'inner CUstream' pub:

   #[derive(Debug)]
   pub struct Stream {
   pub inner: CUstream,
   }

2. I initialize the cublas handle by calling

       unsafe {
           cublas::cublasSetStream_v2(gblas_handle.handle, stream.inner
               as *mut cuda_sys::cudart::CUstream_st );
       }

This appears to cause the blas to run on the same stream as the kernels.

However, I'm a bit uneasy as I'm brute force casing a sys::cuda::CUstream to a sys::cudart::CUstream

I'm not sure about the difference between the two.