O Register File Limitation If each block has 16X16 threads and each thread uses 10 registers, how many thread can run on each SM Each block requires 10* 256=2560 registers 8192=3*2560+ change So. three blocks can run on an sm as far as registers are concerned How about if each thread increases the use of registers by Each Block now requires 11256=2816 registers 8192<2816*3 Only two Blocks can run on an SM, 1/3 reduction of parallelism!!!Register File Limitation 2