Hi Charles, can you please quantify what you mean by 'slower'? How does 'slower' change as you increase the problem size? I would not be surprised if you see no performance gains below matrices of size 500-by-500. With the extra back-and-forth through PCI-Express you may even need matrices of at least 1000-by-1000.
Best regards, Karli On 07/31/2015 09:04 PM, Charles Determan wrote: > Greetings, > > Brief background, I am developing a series of R packages to bring > ViennaCL to the R community. I have had success with the development of > my gpuR package (https://github.com/cdeterman/gpuR) which relies on the > OpenCL backend of ViennaCL (which is housed in the package RViennaCL). > I am hoping to submit to CRAN in the coming weeks now that the latest > stable ViennaCL version has just been released. > > Naturally, I wanted a companion package for a CUDA backend. This is now > the gpuRcuda package (https://github.com/cdeterman/gpuRcuda). This has > appeared to work successfully as most of the code is the same. However, > my initial benchmarks are showing very dismal performance with the CUDA > backend. > > I was wondering if someone from this list would be willing to have a > look at my code to see why the CUDA code would be so much worse. I had > thought, given working a NVIDIA card (GeForce GTX 970), CUDA would > provide improved speed but the benchmarks are showing performance at > least 5-fold slower than the CPU based R multiplication. Even the > 'float' type matrix multiplication is slower than R (which only has > double type support!). > > The sgemm CUDA file is > (https://github.com/cdeterman/gpuRcuda/blob/master/src/vcl_sgemm.cu) and > the associated C++ file is > (https://github.com/cdeterman/gpuRcuda/blob/master/src/vcl_cudaMatrix_gemm.cpp). > > Other note, I have tried making the two packages completely independent > and the performance is still very poor with CUDA. > > I really appreciate any help others could provide troubleshooting this. > I have truly run out of ideas as to why the code has such poor performance. > > Regards, > Charles > > > ------------------------------------------------------------------------------ > > > > _______________________________________________ > ViennaCL-devel mailing list > ViennaCL-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/viennacl-devel > ------------------------------------------------------------------------------ _______________________________________________ ViennaCL-devel mailing list ViennaCL-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/viennacl-devel
