follow dev53, 1. "gpus_per_node = cp.cuda.runtime.getDeviceCount(), local_rank = rank % gpus_per_node!!!" and "checkCudaErrors(cudaSetDevice(getLocalRank())); // !!!!!!"; 2. PyQCU/test/pyqcu/cuda/io.py:get_or_give & try_give add; 3. referring to PyQCU/test/test.clover.bistabcg-np4-test6.log & PyQCU/test/test.clover.bistabcg-np4-test6.log, clover version of bistabcg passes in single node multithreading(4 & 8); 4. 32,64,64,64,double,clover,bistabcg -> 64\*8\*0.15=76.8GB. ^_^