Upload multiple cv::Mat matrices to GPU in one go.

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My application does frame by frame processing on a video and I have to upload a lot of small matrices to the GPU because I'd like to move the computationally intensive parts there.

Could you please tell me how exactly does gpu::GpuMat.upload() work? If I do multple uploads in a row, does openCV send them all at once, or does it do multple transfers? I know an option would be to use enqueueUpload but given that successive frames depend on each other, asynchronous upload is not suitable.