A method includes predicting, for sets of input data, an input data number of a subsequent interval of a first interval using an input data number of the first interval and an input data number of a previous interval of the first interval set in a neural network inference optimization, determining the predicted input data number to be a batch size of the subsequent interval, determining whether pipelining is to be performed in a target device based on a resource state of the target device, and applying, to the target device, an inference policy including the determined batch size and a result of the determining of whether the pipelining is to be performed.