Problem using -l option with double nvidia cards

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the -l parameter is only needed if you want to split the workload to work on gpus of multiple computers. otherwise you do not need to set it. the optimum value depends on the number of computers, the number of cards, the number of SPs of each card per computer, the number of all combinations, the left and the right mask, the -n parameter and the -s parameter. it also depends on if you are on ATI or on NV, because the number of threads are diffrent. but if the value is big enough it is not so important. but generally values that are power of two are good. but if they are to small some gpu power is just wasted.