topologyQuery cudaGetDeviceCount cudaDeviceGetAttribute whole ./ ../ ../../../Common Performance Strategies Multi-GPU peer to peer CUDA Performance multi-GPU support true topologyQuery.cu 1:CUDA Basic Topics 1:Performance Strategies sm50 sm52 sm53 sm60 sm61 sm70 sm72 sm75 sm80 sm86 sm87 sm89 sm90 x86_64 linux windows7 x86_64 macosx ppc64le linux all exe