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 ***@***.***> 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. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#28>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AKUNKJItU6Wwar560RdI7YJznNqf4uvxks5vFjaPgaJpZM4aLlJ2> .

[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.