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StreamHPC / gromacs

OpenCL porting of the GROMACS molecular simulation toolkit
http://www.gromacs.org
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The total number of OpenCL threads depends on the selected OpenCL device #47

Closed ancahamuraru closed 9 years ago

ancahamuraru commented 9 years ago

The total number of threads and the thread configuration changes depending on the selected OpenCL device.

On the same machine, for the same input data, plist->nsci can have different values depending on the selected OpenCL device. Moreover the input data for the OpenCL kernel has a different arrangement, depending on the device.

As an example, for GTX660M, plist->nsci is 395 while for the I7-3610 QM Intel CPU it is 395.

ancahamuraru commented 9 years ago

The difference is explained by the device properties.

For CUDA devices, check multiProcessorCount field from cudaDeviceProp structure and nbnxn_cuda_min_ci_balanced function.

For OpenCL devices, check computeUnits field from ocl_gpu_info_t structure and nbnxn_ocl_min_ci_balanced function.